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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 _search(mapping, filename):
 """Search a Loader data structure for a filename."""

    result = mapping.get(filename)
    if result is not None:
        return result
    name, ext = os.path.splitext(filename)
    result = mapping.get(ext)
    if result is not None:
        for pattern, result2 in result:
            if fnmatch(filename, pattern):
                return result2
    return None