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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 jflatten(j):

 """
 Flatten 3_D Jacobian into 2-D.
 """

    nobs, nf, nargs = j.shape
    nrows, ncols = nf * nobs, nargs * nobs
    jflat = np.zeros((nrows, ncols))
    for n in xrange(nobs):
        r, c = n * nf, n * nargs
        jflat[r:(r + nf), c:(c + nargs)] = j[n]
    return jflat