@value.setter<EOL><INDENT>def value(self, value):<DEDENT>
if value is None or (<EOL>self.ptype is None or isinstance(value, self.ptype)<EOL>):<EOL><INDENT>self._value = value<EOL><DEDENT>else:<EOL><INDENT>error = TypeError(<EOL>'<STR_LIT>'.format(<EOL>self.name, value, self.ptype<EOL>)<EOL>)<EOL>self._error = error<EOL>raise error<EOL><DEDENT>
Change of parameter value.

        If an error occured, it is stored in this error attribute.

        :param value: new value to use. If input value is not an instance of
            self.ptype, self error
        :raises: TypeError if input value is not an instance of self ptype.