code: def _CreateArgItem(arg, docstring_info, spec):
      """Returns a string describing a positional argument.
  
      Args:
        arg: The name of the positional argument.
        docstring_info: A docstrings.DocstringInfo namedtuple with information about
          the containing function's docstring.
        spec: An instance of fire.inspectutils.FullArgSpec, containing type and
         default information about the arguments to a callable.
  
      Returns:
        A string to be used in constructing the help screen for the function.
      """
  
      # The help string is indented, so calculate the maximum permitted length
      # before indentation to avoid exceeding the maximum line length.
      max_str_length = (
          LINE_LENGTH - SECTION_INDENTATION - SUBSECTION_INDENTATION
      )
  
      description = _GetArgDescription(arg, docstring_info)
  
      arg_string = formatting.BoldUnderline(arg.upper())
  
      arg_type = _GetArgType(arg, spec)
      arg_type = "Type: {}".format(arg_type) if arg_type else ""
      available_space = max_str_length - len(arg_type)
      arg_type = formatting.EllipsisTruncate(
          arg_type, available_space, max_str_length
      )
  
      description = "\n".join(
          part for part in (arg_type, description) if part
      )
  
      return _CreateItem(
          arg_string, description, indent=SUBSECTION_INDENTATION
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import itertools
  import sys
  from fire import completion
  from fire import custom_descriptions
  from fire import decorators
  from fire import docstrings
  from fire import formatting
  from fire import inspectutils
  from fire import value_types
label_desc: Use image node_id 17 for calling a global function with example usage: _CreateArgItem(arg, docstring_info, spec) and returns: _CreateItem