def is_lambda(function):
    """
    Checking function to be a lambda function.

    :param function: function to be checked.
    :returns: True when given function is a lambda function.

    >>> square = lambda value: value**2
    >>> is_lambda(square)
    True
    >>> def square2(value): return value**2
    >>> is_lambda(square2)
    False
    >>> is_lambda("hello world")
    False
    """
    LAMBDA = lambda: 0
    return isinstance(function, type(LAMBDA)) and function.__name__ == "<lambda>"