docs: def _apply_units_to_numpy_data_readers(parameters, data):
      """
      Apply units to data originally loaded by :class:`NumPyLoadTxtReader` or
      :class:`NumPyGenFromTxtReader`.
  
      :param parameters: Dictionary of data source parameters read from JSON
          file.
      :type parameters: dict
      :param data: Dictionary of data read
      """
      # apply header units
      header_param = parameters.get('header')  # default is None
      # check for headers
      if header_param:
          fields = header_param['fields']  # header fields
          # dictionary of header field parameters
          header_fields = {field[0]: field[1:] for field in fields}
          # loop over fieldnames
          for k, val in header_fields.iteritems():
              # check for units in header field parameters
              if len(val) > 1:
                  data[k] *= UREG(str(val[1]))  # apply units
      # apply other data units
      data_units = parameters['data'].get('units')  # default is None
      if data_units:
          for k, val in data_units.iteritems():
              data[k] *= UREG(str(val))  # apply units
      return data