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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_summary(self):
 """ Get summary of ``SNPs``. Returns ------- dict summary info, else None if ``SNPs`` is not valid """

        if not self.is_valid():
            return None
        else:
            return {
                "source": self.source,
                "assembly": self.assembly,
                "build": self.build,
                "build_detected": self.build_detected,
                "snp_count": self.snp_count,
                "chromosomes": self.chromosomes_summary,
                "sex": self.sex,
            }