make DCT return typestring with aliases included

PYTHON-579

cassandra/cqltypes.py

@@ -988,6 +988,14 @@ class CompositeType(_ParameterizedType):
 class DynamicCompositeType(CompositeType):
     typename = "org.apache.cassandra.db.marshal.DynamicCompositeType"
 
+    @classmethod
+    def cass_parameterized_type_with(cls, subtypes, full=False, **kwargs):
+        if not full:  # short-circuit for unparsed type
+            return super(DynamicCompositeType, cls).cass_parameterized_type_with(subtypes)
+        # DCT is always formatted "full", and will always have subtypes (otherwise it is normalized to CompositeType by the server)
+        sublist = ', '.join('%s=>%s' % (alias, typ.cass_parameterized_type(full=True)) for alias, typ in zip(cls.fieldnames, subtypes))
+        return '%s(%s)' % (cls.typename, sublist)
+
 
 class ColumnToCollectionType(_ParameterizedType):
     """