code: def format_value(value):
      # type: (Optional[float]) -> str
      if value is None:
          return ""
      elif np.isnan(value):
          return "Missing"
      else:
          return "{:.3f}".format(value)
  
file_path: eli5/eli5/formatters/utils.py
imports: from __future__ import absolute_import
  from itertools import chain
  import re
  import six
  from typing import Any, Union, List, Dict, Callable, Match, Optional
  import numpy
  from eli5.base import Explanation
  from .features import FormattedFeatureName
label_desc: Use image node_id 8 for calling a global function with example usage: format_value(value) and returns: str, str, str