pylint/checkers/utils.py
def is_registered_in_singledispatch_function(node: astroid.FunctionDef) -> bool:
    """Check if the given function node is a singledispatch function."""

    singledispatch_qnames = (
        "functools.singledispatch",
        "singledispatch.singledispatch",
    )

    if not isinstance(node, astroid.FunctionDef):
        return False

    decorators = node.decorators.nodes if node.decorators else []
    for decorator in decorators:
        # func.register are function calls
        if not isinstance(decorator, astroid.Call):
            continue

        func = decorator.func
        if not isinstance(func, astroid.Attribute) or func.attrname != "register":
            continue

        try:
            func_def = next(func.expr.infer())
        except astroid.InferenceError:
            continue

        if isinstance(func_def, astroid.FunctionDef):
            # pylint: disable=redundant-keyword-arg; some flow inference goes wrong here
            return decorated_with(func_def, singledispatch_qnames)

    return False
def is_registered_in_singledispatch_function(node: astroid.FunctionDef) -> bool:
    """Check if the given function node is a singledispatch function."""

    singledispatch_qnames = (
        "functools.singledispatch",
        "singledispatch.singledispatch",
    )

    if not isinstance(node, astroid.FunctionDef):
        return False

    decorators = node.decorators.nodes if node.decorators else []
    for decorator in decorators:
        # func.register are function calls
        if not isinstance(decorator, astroid.Call):
            continue

        func = decorator.func
        if not isinstance(func, astroid.Attribute) or func.attrname != "register":
            continue

        try:
            func_def = next(func.expr.infer())
        except astroid.InferenceError:
            continue

        if isinstance(func_def, astroid.FunctionDef):
            # pylint: disable=redundant-keyword-arg; some flow inference goes wrong here
            return decorated_with(func_def, singledispatch_qnames)

    return False
Check if the given function node is a singledispatch function.