parameters: (self, placeholders, attr)
return_statement: return attr
docstring: Replaces argument placeholders within a single string.
  
      Args:
        placeholders: A dict mapping between placeholder names and their
                      replacement values.
        attr: A string in which to replace argument placeholders.
  
      Returns:
        A string with placeholders replaced, or the same string if no placeholders
        were found.
docstring_summary: Replaces argument placeholders within a single string.
docstring_tokens: Replaces argument placeholders within a single string .
function: def _ReplaceArgumentHelper(self, placeholders, attr):
      """Replaces argument placeholders within a single string.
  
      Args:
        placeholders: A dict mapping between placeholder names and their
                      replacement values.
        attr: A string in which to replace argument placeholders.
  
      Returns:
        A string with placeholders replaced, or the same string if no placeholders
        were found.
      """
      match_placeholder = '\\${([a-zA-Z]*)}'
  
      # Returns the replacement string for found matches.
      def PlaceholderReplacer(matchobj):
        found_placeholder = matchobj.group(1)
        if found_placeholder not in placeholders:
          raise UndefinedPlaceholderException(
              'Undefined placeholder when substituting arguments: '
              + found_placeholder)
        return placeholders[found_placeholder]
  
      attr = re.sub(match_placeholder, PlaceholderReplacer, attr)
  
      return attr
function_tokens: def _ReplaceArgumentHelper ( self , placeholders , attr ) : match_placeholder = '\\${([a-zA-Z]*)}' # Returns the replacement string for found matches. def PlaceholderReplacer ( matchobj ) : found_placeholder = matchobj . group ( 1 ) if found_placeholder not in placeholders : raise UndefinedPlaceholderException ( 'Undefined placeholder when substituting arguments: ' + found_placeholder ) return placeholders [ found_placeholder ] attr = re . sub ( match_placeholder , PlaceholderReplacer , attr ) return attr