code: def bind_target(self, target, ctx=None):
          
  
          # process self _bind_target
          result = self._bind_target(target=target, ctx=ctx)
  
          # fire on bind target event
          self.on_bind_target(target=target, ctx=ctx)
  
          return result
docs: Bind self annotation to target.
  
          :param target: target to annotate.
          :param ctx: target ctx.
          :return: bound target.