class_docstr: ASCII characters outside the ascii-printable range found
class_docstr_tok: ["ASCII","characters","outside","the","ascii-printable","range","found"]
code: def __str__(self):
      return (
          "the following ASCII non-printables found in header: "
          "{}".format(self.non_printables)
      )
  
label_desc: Use image node_id 2 for calling the NonPrintableDefect obj's underlying member method code with example usage: obj.__str__() and returns: str