class_docstr: Static Expression
  
  This kind of feature will load data from provider
class_docstr_tok: ["Static","Expression","This","kind","of","feature","will","load","data","from","provider"]
code: def _load_internal(self, instrument, start_index, end_index, freq):
      # load
      from .data import FeatureD  # pylint: disable=C0415
  
      return FeatureD.feature(
          instrument, str(self), start_index, end_index, freq
      )
  
imports: from __future__ import division
  from __future__ import print_function
  import abc
  import pandas
  from ..log import get_module_logger
label_desc: Use image node_id 3 for calling the Feature obj's underlying member method code with example usage: obj._load_internal(instrument, start_index, end_index, freq) and returns: FeatureD