Write some code, that will flatten an array of arbitrarily nested arrays of integers into a flat array of integers. e.g. [[1,2,[3]],4] -> [1,2,3,4].

flattern_array.py

array = [[1,2,[3]],4]

def arrayFlat(arr, newArray = []):
    """Function that receives an array of integers, there can be nested array
    elements, and returns the flattened version of the given aray"""
    for el in arr:
        if not isinstance(el, list):
            newArray.append(el)
        else:
            arrayFlat(el, newArray)
    return newArray

if __name__ == '__main__':
    print arrayFlat(array)