Iterate passed read group ids, or go through all available read groups

def run(self):
        """
        Iterate passed read group ids, or go through all available read groups
        """
        if not self._readGroupIds:
            for referenceGroupId in self.getAllReadGroups():
                self._run(referenceGroupId)
        else:
            for referenceGroupId in self._readGroupIds:
                self._run(referenceGroupId)