How to uniformly handle A LIST or A LIST OF LIST (multi-dimensional list)
<p>Without any heavy libraries such as numpy, I want to uniformly handle a single list or multi-dimensional list in my code. For example, the function sum_up(list_or_matrix) should 
return 6 for argument [1, 2, 3] and return 9 for [[1, 2, 3], [1, 2, 0]].</p>

<p>My question is:
1. Can I code in a way without explicitly detecting the dimension of my input such as by isinstance(arg[0], (tuple, list))? <p>
2. If I have to do so, is there any elegant way of detecting the dimension of a list (of list of list ...), e.g. recursively?</p>
