docs: def edit(self, data_src, value):
          """
          Edit data layer.
  
          :param data_src: Name of :class:`DataSource` to edit.
          :type data_src: str
          :param value: Values to edit.
          :type value: dict
          """
          # check if opening file
          if 'filename' in value:
              items = [k for k, v in self.reg.data_source.iteritems() if
                       v == data_src]
              self.reg.unregister(items)  # remove items from Registry
              # open file and register new data
              self.open(data_src, value['filename'], value.get('path'))
              self.layer[data_src].update(value)