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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 add_default_handler(ioclass, format, extension=None):
 """Register a new data handler for a given format in the default handler list. This is a convenience function used internally to setup the default handlers. It can be used to add other handlers at runtime even if this isn't a suggested practice. **Parameters** ioclass: IOHandler subclass format: str A string identifier representing the format extension: str, optional The file extension associated with the format. """

    if format in _handler_map:
        print("Warning: format {} already present.".format(format))

    _handler_map[format] = ioclass

    if extension in _extensions_map:
        print("Warning: extension {} already handled by {} handler."
              .format(extension, _extensions_map[extension]))

    if extension is not None:
        _extensions_map[extension] = format