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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 is_active(ext, metadata):
 """Is the cell active for the given file extension?"""

    if metadata.get('run_control', {}).get('frozen') is True:
        return False
    if 'active' not in metadata:
        return True
    return ext.replace('.', '') in re.split('\\.|,', metadata['active'])