code: def _overlapOK(self, i, j, overlap=None):
      
      if overlap is None:
        overlap = self._countOverlapIndices(i, j)
      if abs(i-j) < self.w:
        if overlap == (self.w - abs(i-j)):
          return True
        else:
          return False
      else:
        if overlap <= self._maxOverlap:
          return True
        else:
          return False
docs: Return True if the given overlap between bucket indices i and j are
      acceptable. If overlap is not specified, calculate it from the bucketMap