{{alias}}( obj1, obj2[, ...obj] )
    Returns the common own and inherited property names of two or more objects.

    Parameters
    ----------
    obj1: any
        First object.

    obj2: any
        Second object.

    obj: ...any (optional)
        Additional objects.

    Returns
    -------
    out: Array<string>
        Common keys.

    Examples
    --------
    > var obj1 = { 'a': 1, 'b': 2 };
    > var obj2 = { 'a': 1, 'b': 2, 'c': 3, 'd': 4 };
    > var keys = {{alias}}( obj1, obj2 )
    [ 'a', 'b' ]

    See Also
    --------