'Return all available class names beginning with expr'

def _classes_from_scope(self, expr, scoperef, allowGlobalClasses=False):

    lookup_scopes = ('locals', 'namespace', 'globals', 'imports')
    if ((not allowGlobalClasses) and self._namespace_elem_from_scoperef(scoperef)):
        lookup_scopes = ('locals', 'namespace')
    return self._element_names_from_scope_starting_with_expr(expr, scoperef, 'class', lookup_scopes, self.class_names_from_elem)
