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Small Python modernization of Brotli code.
PiperOrigin-RevId: 549289787
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102
python/bro.py
102
python/bro.py
@ -1,7 +1,11 @@
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#! /usr/bin/env python
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#! /usr/bin/env python
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"""Compression/decompression utility using the Brotli algorithm."""
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"""Compression/decompression utility using the Brotli algorithm."""
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# Note: Python2 has been deprecated long ago, but some projects out in
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# the wide world may still use it nevertheless. This should not
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# deprive them from being able to run Brotli.
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from __future__ import print_function
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from __future__ import print_function
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import argparse
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import argparse
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import os
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import os
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import platform
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import platform
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@ -9,8 +13,9 @@ import sys
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import brotli
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import brotli
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# default values of encoder parameters
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# default values of encoder parameters
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DEFAULT_PARAMS = {
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_DEFAULT_PARAMS = {
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'mode': brotli.MODE_GENERIC,
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'mode': brotli.MODE_GENERIC,
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'quality': 11,
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'quality': 11,
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'lgwin': 22,
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'lgwin': 22,
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@ -19,17 +24,32 @@ DEFAULT_PARAMS = {
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def get_binary_stdio(stream):
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def get_binary_stdio(stream):
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""" Return the specified standard input, output or errors stream as a
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"""Return the specified stdin/stdout/stderr stream.
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'raw' buffer object suitable for reading/writing binary data from/to it.
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If the stdio stream requested (i.e. sys.(stdin|stdout|stderr))
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has been replaced with a stream object that does not have a `.buffer`
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attribute, this will return the original stdio stream's buffer, i.e.
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`sys.__(stdin|stdout|stderr)__.buffer`.
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Args:
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stream: One of 'stdin', 'stdout', 'stderr'.
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Returns:
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The stream, as a 'raw' buffer object (i.e. io.BufferedIOBase subclass
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instance such as io.Bufferedreader/io.BufferedWriter), suitable for
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reading/writing binary data from/to it.
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"""
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"""
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assert stream in ['stdin', 'stdout', 'stderr'], 'invalid stream name'
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if stream == 'stdin': stdio = sys.stdin
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stdio = getattr(sys, stream)
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elif stream == 'stdout': stdio = sys.stdout
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elif stream == 'stderr': stdio = sys.stderr
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else:
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raise ValueError('invalid stream name: %s' % (stream,))
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if sys.version_info[0] < 3:
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if sys.version_info[0] < 3:
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if sys.platform == 'win32':
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if sys.platform == 'win32':
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# set I/O stream binary flag on python2.x (Windows)
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# set I/O stream binary flag on python2.x (Windows)
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runtime = platform.python_implementation()
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runtime = platform.python_implementation()
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if runtime == 'PyPy':
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if runtime == 'PyPy':
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# the msvcrt trick doesn't work in pypy, so I use fdopen
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# the msvcrt trick doesn't work in pypy, so use fdopen().
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mode = 'rb' if stream == 'stdin' else 'wb'
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mode = 'rb' if stream == 'stdin' else 'wb'
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stdio = os.fdopen(stdio.fileno(), mode, 0)
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stdio = os.fdopen(stdio.fileno(), mode, 0)
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else:
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else:
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@ -38,12 +58,20 @@ def get_binary_stdio(stream):
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msvcrt.setmode(stdio.fileno(), os.O_BINARY)
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msvcrt.setmode(stdio.fileno(), os.O_BINARY)
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return stdio
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return stdio
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else:
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else:
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# get 'buffer' attribute to read/write binary data on python3.x
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try:
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if hasattr(stdio, 'buffer'):
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return stdio.buffer
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return stdio.buffer
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else:
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except AttributeError:
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orig_stdio = getattr(sys, '__%s__' % stream)
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# The Python reference explains
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return orig_stdio.buffer
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# (-> https://docs.python.org/3/library/sys.html#sys.stdin)
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# that the `.buffer` attribute might not exist, since
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# the standard streams might have been replaced by something else
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# (such as an `io.StringIO()` - perhaps via
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# `contextlib.redirect_stdout()`).
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# We fall back to the original stdio in these cases.
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if stream == 'stdin': return sys.__stdin__.buffer
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if stream == 'stdout': return sys.__stdout__.buffer
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if stream == 'stderr': return sys.__stderr__.buffer
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assert False, 'Impossible Situation.'
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def main(args=None):
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def main(args=None):
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@ -114,46 +142,52 @@ def main(args=None):
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help='Base 2 logarithm of the maximum input block size. '
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help='Base 2 logarithm of the maximum input block size. '
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'Range is 16 to 24. If set to 0, the value will be set based '
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'Range is 16 to 24. If set to 0, the value will be set based '
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'on the quality. Defaults to 0.')
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'on the quality. Defaults to 0.')
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# set default values using global DEFAULT_PARAMS dictionary
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# set default values using global _DEFAULT_PARAMS dictionary
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parser.set_defaults(**DEFAULT_PARAMS)
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parser.set_defaults(**_DEFAULT_PARAMS)
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options = parser.parse_args(args=args)
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options = parser.parse_args(args=args)
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if options.infile:
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if options.infile:
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if not os.path.isfile(options.infile):
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try:
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parser.error('file "%s" not found' % options.infile)
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with open(options.infile, 'rb') as infile:
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with open(options.infile, 'rb') as infile:
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data = infile.read()
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data = infile.read()
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except OSError:
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parser.error('Could not read --infile: %s' % (infile,))
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else:
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else:
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if sys.stdin.isatty():
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if sys.stdin.isatty():
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# interactive console, just quit
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# interactive console, just quit
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parser.error('no input')
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parser.error('No input (called from interactive terminal).')
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infile = get_binary_stdio('stdin')
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infile = get_binary_stdio('stdin')
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data = infile.read()
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data = infile.read()
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if options.outfile:
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if options.outfile:
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if os.path.isfile(options.outfile) and not options.force:
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# Caution! If `options.outfile` is a broken symlink, will try to
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parser.error('output file exists')
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# redirect the write according to symlink.
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if os.path.exists(options.outfile) and not options.force:
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parser.error(('Target --outfile=%s already exists, '
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'but --force was not requested.') % (outfile,))
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outfile = open(options.outfile, 'wb')
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outfile = open(options.outfile, 'wb')
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did_open_outfile = True
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else:
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else:
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outfile = get_binary_stdio('stdout')
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outfile = get_binary_stdio('stdout')
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did_open_outfile = False
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try:
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try:
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if options.decompress:
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try:
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data = brotli.decompress(data)
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if options.decompress:
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else:
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data = brotli.decompress(data)
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data = brotli.compress(
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else:
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data,
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data = brotli.compress(
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mode=options.mode,
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data,
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quality=options.quality,
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mode=options.mode,
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lgwin=options.lgwin,
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quality=options.quality,
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lgblock=options.lgblock)
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lgwin=options.lgwin,
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lgblock=options.lgblock)
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outfile.write(data)
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finally:
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if did_open_outfile: outfile.close()
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except brotli.error as e:
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except brotli.error as e:
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parser.exit(1,
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parser.exit(1,
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'bro: error: %s: %s' % (e, options.infile or 'sys.stdin'))
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'bro: error: %s: %s' % (e, options.infile or '{stdin}'))
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outfile.write(data)
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outfile.close()
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if __name__ == '__main__':
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if __name__ == '__main__':
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