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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 chimera_layout(G, scale=1., center=None, dim=2):
 """Positions the nodes of graph G in a Chimera cross topology. NumPy (http://scipy.org) is required for this function. Parameters G : NetworkX graph Should be a Chimera graph or a subgraph of a Chimera graph. If every node in G has a `chimera_index` attribute, those are used to place the nodes. Otherwise makes a best-effort attempt to find positions. scale : float (default 1.) Scale factor. When scale = 1, all positions fit within [0, 1] on the x-axis and [-1, 0] on the y-axis. center : None or array (default None) Coordinates of the top left corner. dim : int (default 2) Number of dimensions. When dim > 2, all extra dimensions are set to 0. Returns ------- pos : dict A dictionary of positions keyed by node. Examples -------- """


    if not isinstance(G, nx.Graph):
        empty_graph = nx.Graph()
        empty_graph.add_edges_from(G)
        G = empty_graph

    # now we get chimera coordinates for the translation
    # first, check if we made it
    if G.graph.get("family") == "chimera":
        m = G.graph['rows']
        n = G.graph['columns']
        t = G.graph['tile']
        # get a node placement function
        xy_coords = chimera_node_placer_2d(m, n, t, scale, center, dim)

        if G.graph.get('labels') == 'coordinate':
            pos = {v: xy_coords(*v) for v in G.nodes()}
        elif G.graph.get('data'):
            pos = {v: xy_coords(*dat['chimera_index']) for v, dat in G.nodes(data=True)}
        else:
            coord = chimera_coordinates(m, n, t)
            pos = {v: xy_coords(*coord.tuple(v)) for v in G.nodes()}
    else:
        # best case scenario, each node in G has a chimera_index attribute. Otherwise
        # we will try to determine it using the find_chimera_indices function.
        if all('chimera_index' in dat for __, dat in G.nodes(data=True)):
            chimera_indices = {v: dat['chimera_index'] for v, dat in G.nodes(data=True)}
        else:
            chimera_indices = find_chimera_indices(G)

        # we could read these off of the name attribute for G, but we would want the values in
        # the nodes to override the name in case of conflict.
        m = max(idx[0] for idx in itervalues(chimera_indices)) + 1
        n = max(idx[1] for idx in itervalues(chimera_indices)) + 1
        t = max(idx[3] for idx in itervalues(chimera_indices)) + 1
        xy_coords = chimera_node_placer_2d(m, n, t, scale, center, dim)

        # compute our coordinates
        pos = {v: xy_coords(i, j, u, k) for v, (i, j, u, k) in iteritems(chimera_indices)}

    return pos