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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 GetPresetByName(self, name):
 """Retrieves a specific preset definition by name. Args: name (str):
 name of the preset. Returns: ParserPreset: a parser preset or None if not available. """

    name = name.lower()
    return self._definitions.get(name, None)