def setDeclaration(self, declaration):
        """ Set the declaration this model will use for rendering
        the the headers. 
        
        """
        assert isinstance(declaration.proxy, ProxyAbstractItemView), \
            "The model declaration must be a QtAbstractItemView subclass. " \
            "Got {]".format(declaration)

        self.declaration = declaration
Set the declaration this model will use for rendering
        the the headers.