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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 is_deletion(self):
 """ Does this variant represent the deletion of nucleotides from the reference genome? """

        # A deletion would appear in a VCF like CT>C, so that the
        # reference allele starts with the alternate nucleotides.
        # This is true even in the normalized case, where the alternate
        # nucleotides are an empty string.
        return (len(self.ref) > len(self.alt)) and self.ref.startswith(self.alt)