code: def render(self, ctx=None):
          '''
          Render only the mutated field (or the first one if not in mutation)
  
          :param ctx: rendering context in which the method was called
          :rtype: `Bits`
          :return: rendered value of the container
          '''
          if ctx is None:
              ctx = RenderContext()
          ctx.push(self)
          self._initialize()
          offset = self.offset if self.offset else 0
          self._fields[self._field_idx].set_offset(offset)
          rendered = self._fields[self._field_idx].render(ctx)
          self.set_current_value(rendered)
          ctx.pop()
          return self._current_renderef render(self, ctx=None):
          '''
          Render only the mutated field (or the first one if not in mutation)
  
          :param ctx: rendering context in which the method was called
          :rtype: `Bits`
          :return: rendered value of the container
          '''
          if ctx is None:
              ctx = RenderContext()
          ctx.push(self)
          self._initialize()
          offset = self.offset if self.offset else 0
          self._fields[self._field_idx].set_offset(offset)
          rendered = self._fields[self._field_idx].render(ctx)
          self.set_current_value(rendered)
          ctx.pop()
          return self._current_rendered
docs: Render only the mutated field (or the first one if not in mutation)
  
          :param ctx: rendering context in which the method was called
          :rtype: `Bits`
          :return: rendered value of the container