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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 guess_strategy_type(file_name_or_ext):
 """Guess strategy type to use for file by extension. Args: file_name_or_ext: Either a file name with an extension or just an extension Returns: Strategy: Type corresponding to extension or None if there's no corresponding strategy type """

    if '.' not in file_name_or_ext:
        ext = file_name_or_ext
    else:
        name, ext = os.path.splitext(file_name_or_ext)
    ext = ext.lstrip('.')
    file_type_map = get_file_type_map()
    return file_type_map.get(ext, None)