code: def _gate_width(self, gate):
          
          try:
              gates = self.settings['gates']
              gate_width = gates[gate.__class__.__name__]['width']
          except KeyError:
              gate_width = .5
          return gate_width
docs: Return the gate width, using the settings (if available).
  
          :param string gate: The name of the gate whose height is desired.
          :return: Width of the gate.
          :rtype: float