'Dictionary-like object of keys from POST, GET, URL dicts
Return a key value from the parameters, they are checked in the
following order: POST, GET, URL
Additional methods supported:
``getlist(key)``
Returns a list of all the values by that key, collected from
POST, GET, URL dicts
Returns a ``MultiDict`` container or a ``UnicodeMultiDict`` when
``charset`` is set.'

def params(self):

    params = MultiDict()
    params.update(self._POST())
    params.update(self._GET())
    if self.charset:
        params = UnicodeMultiDict(params, encoding=self.charset, errors=self.errors, decode_keys=self.decode_param_names)
    return params
