code: def get_feature_list_size(key, sequence, prefix=""):
      if has_feature_list(merge_prefix(prefix, key), sequence):
          return len(
              sequence.feature_lists.feature_list[
                  merge_prefix(prefix, key)
              ].feature
          )
      else:
          return 0
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import types
  import tensorflow.compat.v1
label_desc: Use image node_id 19 for calling a global function with example usage: get_feature_list_size(key, sequence, prefix) and returns: len, int