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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 getPysamVariants(self, referenceName, startPosition, endPosition):
 """ Returns an iterator over the pysam VCF records corresponding to the specified query. """

        if referenceName in self._chromFileMap:
            varFileName = self._chromFileMap[referenceName]
            referenceName, startPosition, endPosition = \
                self.sanitizeVariantFileFetch(
                    referenceName, startPosition, endPosition)
            cursor = self.getFileHandle(varFileName).fetch(
                referenceName, startPosition, endPosition)
            for record in cursor:
                yield record