Code to handle messages defined in

https://openid.net/specs/openid-connect-4-identity-assurance-1_0-ID1.html

Author: rohe

src/oidcmsg/message.py

@@ -338,6 +338,12 @@ def _add_value(self, skey, vtyp, key, val, _deser, null_allowed):
             vtyp = vtyp[0]
 
         if isinstance(vtyp, list):
+            if val is None:
+                if null_allowed:
+                    self._dict[key] = val
+                    return
+                raise ValueError("Null is not allowed")
+
             vtype = vtyp[0]
             if isinstance(val, vtype):
                 if issubclass(vtype, Message):
@@ -824,6 +830,18 @@ def required_parameters(self):
         """
         return [p for p, s in self.c_param.items() if s[1] is True]
 
+    def value_type(self, parameter):
+        """
+        Return the type of value that a parameter can have.
+
+        :param parameter: Name of the parameter
+        :return: Type of Value or None if unknown.
+        """
+        _spec = self.c_param.get(parameter)
+        if _spec:
+            return _spec[0]
+
+        return None
 
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