code: def change_thickness(self, element, thickness):
          r
  
          if element == "header":
              self.data.append(Command("renewcommand",
                               arguments=[NoEscape(r"\headrulewidth"),
                                          str(thickness) + 'pt']))
          elif element == "footer":
              self.data.append(Command("renewcommand", arguments=[
                  NoEscape(r"\footrulewidth"), str(thickness) + 'pt']))
docs: r"""Change line thickness.
  
          Changes the thickness of the line under/over the header/footer
          to the specified thickness.
  
          Args
          ----
          element: str
              the name of the element to change thickness for: header, footer
          thickness: float
              the thickness to set the line to