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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_change_type(self, ref, a1, a2):
 """ Given ref, allele1, and allele2, returns the type of change. The only case of an amino acid insertion is when the ref is represented as a '.'. """

        if ref == '.':
            return self.INSERTION
        elif a1 == '.' or a2 == '.':
            return self.DELETION