code: def find_matching_bracket_position(self, start_pos=None, end_pos=None):
          
  
          # Look for a match.
          for A, B in '()', '[]', '{}', '<>':
              if self.current_char == A:
                  return self.find_enclosing_bracket_right(A, B, end_pos=end_pos) or 0
              elif self.current_char == B:
                  return self.find_enclosing_bracket_left(A, B, start_pos=start_pos) or 0
  
          return 0
docs: Return relative cursor position of matching [, (, { or < bracket.
  
          When `start_pos` or `end_pos` are given. Don't look past the positions.