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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def k_array_rank_jit(a):
 """ Numba jit version of `k_array_rank`. Notes ----- An incorrect value will be returned without warning or error if overflow occurs during the computation. It is the user's responsibility to ensure that the rank of the input array fits within the range of possible values of `np.intp`; a sufficient condition for it is `scipy.special.comb(a[-1]+1, len(a), exact=True) <= np.iinfo(np.intp).max`. """

    k = len(a)
    idx = a[0]
    for i in range(1, k):
        idx += comb_jit(a[i], i+1)
    return idx