code: def infographic_header_element(impact_function_name, feature, parent):
      
      _ = feature, parent  # NOQA
      string_format = infographic_header['string_format']
      if impact_function_name:
          header = string_format.format(
              impact_function_name=impact_function_name)
          return header.capitalize()
      return None
docs: Get a formatted infographic header sentence for an impact function.
  
      For instance:
      * infographic_header_element('flood') -> 'Estimated impact of a flood'