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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 getFields(cls) : 		"""returns a set of the available fields. In order to be able ti securely loop of the fields, "raba_id" and "json" are not included in the set"""

		s = set(cls.columns.keys())
		s.remove('json')
		s.remove('raba_id')
		return s