code: def pi_info(revision=None):
      
      if revision is None:
          if Device.pin_factory is None:
              Device.pin_factory = Device._default_pin_factory()
          result = Device.pin_factory.pi_info
          if result is None:
              raise PinUnknownPi('The default pin_factory is not attached to a Pi')
          else:
              return result
      else:
          if isinstance(revision, bytes):
              revision = revision.decode('ascii')
          if isinstance(revision, str):
              revision = int(revision, base=16)
          else:
              # be nice to people passing an int (or something numeric anyway)
              revision = int(revision)
          return PiBoardInfo.from_revision(revision)
docs: Returns a :class:`PiBoardInfo` instance containing information about a
      *revision* of the Raspberry Pi.
  
      :param str revision:
          The revision of the Pi to return information about. If this is omitted
          or :data:`None` (the default), then the library will attempt to determine
          the model of Pi it is running on and return information about that.