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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 _parse_exclude(exclude_file):
    '''
    Parse an exclude file.

    Returns a dict as defined in gentoolkit.eclean.exclude.parseExcludeFile
    '''
    if os.path.isfile(exclude_file):
        exclude = excludemod.parseExcludeFile(exclude_file, lambda x: None)
    else:
        exclude = dict()
    return exclude