@default.setter<EOL><INDENT>def default(self, value):<DEDENT>
if value is None:<EOL><INDENT>if self:<EOL><INDENT>value = list(self.keys())[<NUM_LIT:0>]<EOL><DEDENT><DEDENT>elif not isinstance(value, string_types):<EOL><INDENT>value = register(exprresolver=value, reg=self)<EOL><DEDENT>elif value not in self:<EOL><INDENT>raise KeyError(<EOL>'<STR_LIT>'.format(value, self)<EOL>)<EOL><DEDENT>self._default = value<EOL>
Change of resolver name.

        :param value: new default value to use.
        :type value: str or callable
        :raises: KeyError if value is a string not already registered.