code: func (s *stack) PopInt() (scriptNum, error) {
  	so, err := s.PopByteArray()
  	if err != nil {
  		return 0, err
  	}
  
  	return makeScriptNum(so, s.verifyMinimalData, defaultScriptNumLen)
  }
docs: // PopInt pops the value off the top of the stack, converts it into a script
  // num, and returns it.  The act of converting to a script num enforces the
  // consensus rules imposed on data interpreted as numbers.
  //
  // Stack transformation: [... x1 x2 x3] -> [... x1 x2]