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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 caseinsensitive(cls):
 """Annotation function to set an Enum to be case insensitive on parsing"""

    if not issubclass(cls, Enum):
        raise TypeError('caseinsensitive decorator can only be applied to subclasses of enum.Enum')
    enum_options = getattr(cls, PYCKSON_ENUM_OPTIONS, {})
    enum_options[ENUM_CASE_INSENSITIVE] = True
    setattr(cls, PYCKSON_ENUM_OPTIONS, enum_options)
    return cls