Define list type from all elements type (or empty_list type).

def visit_List(self, node):
        """ Define list type from all elements type (or empty_list type). """
        self.generic_visit(node)
        if node.elts:
            for elt in node.elts:
                self.combine(node, elt, unary_op=self.builder.ListType)
        else:
            self.result[node] = self.builder.NamedType(
                "pythonic::types::empty_list")