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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 get_evcodes(self, inc_set=None, exc_set=None):
 """Get evidence code for all but NOT 'No biological data'"""

        codes = self.get_evcodes_all(inc_set, exc_set)
        codes.discard('ND')
        return codes