Example 1:

        In[1]: source = 'abc'

        In[2]: a, b = unpack(source, 2)

        In[3]: print(a, b)

        a b

Example 2:

        In[1]: source = 'abc'

        In[2]: a, b, c, d = unpack(source, 4)

        In[3]: print(a, b, c, d)

        a b None None

@accepts(iterable='__iter__', count=int)

def unpack(iterable, count, fill=None):

    """

    The iter data unpack function.

    """

    iterable = list(enumerate(iterable))

    cnt = count if count <= len(iterable) else len(iterable)

    results = [iterable[i][1] for i in range(cnt)]

    # results[len(results):len(results)] = [fill for i in range(count-cnt)]

    results = merge(results, [fill for i in range(count-cnt)])

    return tuple(results)