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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 comment_out_magics(source):
 """ Utility used to make sure AST parser does not choke on unrecognized magics. """

    filtered = []
    for line in source.splitlines():
        if line.strip().startswith('%'):
            filtered.append('# ' +  line)
        else:
            filtered.append(line)
    return '\n'.join(filtered)