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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 derivative(f, t):
 """Fourth-order finite-differencing with non-uniform time steps The formula for this finite difference comes from Eq. (A 5b) of "Derivative formulas and errors for non-uniformly spaced points" by M. K. Bowen and Ronald Smith. As explained in their Eqs. (B 9b) and (B 10b), this is a fourth-order formula -- though that's a squishy concept with non-uniform time steps. TODO: If there are fewer than five points, the function should revert to simpler (lower-order) formulas. """

    dfdt = np.empty_like(f)
    if (f.ndim == 1):
        _derivative(f, t, dfdt)
    elif (f.ndim == 2):
        _derivative_2d(f, t, dfdt)
    elif (f.ndim == 3):
        _derivative_3d(f, t, dfdt)
    else:
        raise NotImplementedError("Taking derivatives of {0}-dimensional arrays is not yet implemented".format(f.ndim))
    return dfdt