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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def normalize_files(files, separators=None):
 	""" 	Normalizes the file paths to use the POSIX path separator. 	*files* (:class:`~collections.abc.Iterable` of :class:`str`) contains 	the file paths to be normalized. 	*separators* (:class:`~collections.abc.Collection` of :class:`str`; or 	:data:`None`) optionally contains the path separators to normalize. 	See :func:`normalize_file` for more information. 	Returns a :class:`dict` mapping the each normalized file path (:class:`str`) 	to the original file path (:class:`str`) 	"""

	norm_files = {}
	for path in files:
		norm_files[normalize_file(path, separators=separators)] = path
	return norm_files