def sizeOfOverlap(self, e):
    """
    Get the size of the overlap between self and e.

    :return: the number of bases that are shared in common between self and e.
    """
    # no overlap
    if not self.intersects(e):
      return 0

    # complete inclusion..
    if e.start >= self.start and e.end <= self.end:
      return len(e)
    if self.start >= e.start and self.end <= e.end:
      return len(self)

    # partial overlap
    if e.start > self.start:
      return (self.end - e.start)
    if self.start > e.start:
      return (e.end - self.start)
Get the size of the overlap between self and e.

    :return: the number of bases that are shared in common between self and e.