import ast


def is_empty_string(node: ast.AST) -> bool:
    """
    Checks if the node is a constant empty string.
    """

    # empty string literal
    if isinstance(node, ast.Str) and not node.s:
        return True

    # empty f-string
    if isinstance(node, ast.JoinedStr) and not node.values:
        return True

    return False