class_docstr: Raised if click required an option or argument but it was not
  provided when invoking the script.
  
  .. versionadded:: 4.0
  
  :param param_type: a string that indicates the type of the parameter.
                     The default is to inherit the parameter type from
                     the given `param`.  Valid values are ``'parameter'``,
                     ``'option'`` or ``'argument'``.
class_docstr_tok: ["Raised","if","click","required","an","option","or","argument","but","it","was","not","provided","when","invoking","the","script",".","..","versionadded",":",":","4.0",":","param","param_type",":","a","string","that","indicates","the","type","of","the","parameter",".","The","default","is","to","inherit","the","parameter","type","from","the","given","`","param","`",".","Valid","values","are","``","'parameter","'","``",",","``","'option","'","``","or","``","'argument","'","``","."]
code: def __str__(self) -> str:
      if not self.message:
          param_name = self.param.name if self.param else None
          return _("Missing parameter: {param_name}").format(
              param_name=param_name
          )
      else:
          return self.message
  
imports: import typing
  from gettext import gettext
  from gettext import ngettext
  from ._compat import get_text_stderr
  from .utils import echo
  from .utils import format_filename
label_desc: Use image node_id 3 for calling the MissingParameter obj's underlying member method code with example usage: obj.__str__() and returns: _, self