code: def _fix_names(field_spec):
      """Replace names which are None with the next unused f%d name"""
      names = field_spec["names"]
      for i, name in enumerate(names):
          if name is not None:
              continue
  
          j = 0
          while True:
              name = f"f{j}"
              if name not in names:
                  break
              j = j + 1
          names[i] = name
  
imports: import ast
  import re
  import sys
  import warnings
  from ..exceptions import DTypePromotionError
  from .multiarray import dtype, array, ndarray, promote_types
label_desc: Use image node_id 14 for calling a global function with example usage: _fix_names(field_spec) without return types