def array_find(arr, obj) -> int:
    """A helpher function which finds the index of an object in an array.
       Instead of throwing an error when no index can be found it returns -1.

    Args:
        arr : the array to be searched
        obj : the object whose index is to be found.

    Returns:
        int: The index of obj in the array. -1 if the object is not in the array
    """
    index = -1
    try:
        index = arr.index(obj)
        return index
    except:
        return -1