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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 dp_from_p(p, ps, p_top=0., p_bot=1.1e5):
 """Get level thickness of pressure data, incorporating surface pressure. Level edges are defined as halfway between the levels, as well as the user- specified uppermost and lowermost values. The dp of levels whose bottom pressure is less than the surface pressure is not changed by ps, since they don't intersect the surface. If ps is in between a level's top and bottom pressures, then its dp becomes the pressure difference between its top and ps. If ps is less than a level's top and bottom pressures, then that level is underground and its values are masked. Note that postprocessing routines (e.g. at GFDL) typically mask out data wherever the surface pressure is less than the level's given value, not the level's upper edge. This masks out more levels than the """

    p_str = get_dim_name(p, (internal_names.PLEVEL_STR, 'plev'))
    p_vals = to_pascal(p.values.copy())

    # Layer edges are halfway between the given pressure levels.
    p_edges_interior = 0.5*(p_vals[:-1] + p_vals[1:])
    p_edges = np.concatenate(([p_bot], p_edges_interior, [p_top]))
    p_edge_above = p_edges[1:]
    p_edge_below = p_edges[:-1]
    dp = p_edge_below - p_edge_above
    if not all(np.sign(dp)):
        raise ValueError("dp array not all > 0 : {}".format(dp))
    # Pressure difference between ps and the upper edge of each pressure level.
    p_edge_above_xr = xr.DataArray(p_edge_above, dims=p.dims, coords=p.coords)
    dp_to_sfc = ps - p_edge_above_xr
    # Find the level adjacent to the masked, under-ground levels.
    change = xr.DataArray(np.zeros(dp_to_sfc.shape), dims=dp_to_sfc.dims,
                          coords=dp_to_sfc.coords)
    change[{p_str: slice(1, None)}] = np.diff(
        np.sign(ps - to_pascal(p.copy()))
    )
    dp_combined = xr.DataArray(np.where(change, dp_to_sfc, dp),
                               dims=dp_to_sfc.dims, coords=dp_to_sfc.coords)
    # Mask levels that are under ground.
    above_ground = ps > to_pascal(p.copy())
    above_ground[p_str] = p[p_str]
    dp_with_ps = dp_combined.where(above_ground)
    # Revert to original dim order.
    possible_dim_orders = [
        (internal_names.TIME_STR, p_str, internal_names.LAT_STR,
         internal_names.LON_STR),
        (internal_names.TIME_STR, p_str, internal_names.LAT_STR),
        (internal_names.TIME_STR, p_str, internal_names.LON_STR),
        (internal_names.TIME_STR, p_str),
        (p_str, internal_names.LAT_STR, internal_names.LON_STR),
        (p_str, internal_names.LAT_STR),
        (p_str, internal_names.LON_STR),
        (p_str,),
    ]
    for dim_order in possible_dim_orders:
        try:
            return dp_with_ps.transpose(*dim_order)
        except ValueError:
            logging.debug("Failed transpose to dims: {}".format(dim_order))
    else:
        logging.debug("No transpose was successful.")
        return dp_with_ps