code: def initial_string_from_tokens(tokens):
      current_index = 0
      s = ""
      for t in tokens:
          if t.start > current_index:
              s += " " * (t.start - current_index)
          s += t.value
          current_index = t.end
      return s
  
imports: from __future__ import unicode_literals
  from copy import deepcopy
  from snips_nlu.common.dict_utils import LimitedSizeDict
  from snips_nlu.constants import END, RES_MATCH_RANGE, START
label_desc: Use image node_id 3 for calling a global function with example usage: initial_string_from_tokens(tokens) and returns: s