Declare a rule.  This allows a default for a given rule to be
        set, along with default values for the authorization
        attributes.  This function can also include documentation for
        the rule and the authorization attributes, allowing a sample
        policy configuration file to be generated.

        :param name: The name of the rule.
        :param text: The text of the rule.  Defaults to the empty
                     string.
        :param doc: A string documenting the purpose of the rule.
        :param attrs: A dictionary of default values for the
                      authorization attributes.  Note that
                      authorization attributes cannot have names
                      beginning with an underscore ("_").
        :param attr_docs: A dictionary of strings for documenting the
                          purpose of the authorization attributes.

def declare(self, name, text='', doc=None, attrs=None, attr_docs=None):
        """
        Declare a rule.  This allows a default for a given rule to be
        set, along with default values for the authorization
        attributes.  This function can also include documentation for
        the rule and the authorization attributes, allowing a sample
        policy configuration file to be generated.

        :param name: The name of the rule.
        :param text: The text of the rule.  Defaults to the empty
                     string.
        :param doc: A string documenting the purpose of the rule.
        :param attrs: A dictionary of default values for the
                      authorization attributes.  Note that
                      authorization attributes cannot have names
                      beginning with an underscore ("_").
        :param attr_docs: A dictionary of strings for documenting the
                          purpose of the authorization attributes.
        """

        self._defaults[name] = rules.Rule(name, text, attrs)
        self._docs[name] = rules.RuleDoc(name, doc, attr_docs)

        return self._defaults[name]