code: def color_greedy(self):
      '''Returns a greedy vertex coloring as an array of ints.'''
      n = self.num_vertices()
      coloring = np.zeros(n, dtype=int)
      for i, nbrs in enumerate(self.adj_list()):
        nbr_colors = set(coloring[nbrs])
        for c in count(1):
          if c not in nbr_colors:
            coloring[i] = c
            break
      return colorinf color_greedy(self):
      '''Returns a greedy vertex coloring as an array of ints.'''
      n = self.num_vertices()
      coloring = np.zeros(n, dtype=int)
      for i, nbrs in enumerate(self.adj_list()):
        nbr_colors = set(coloring[nbrs])
        for c in count(1):
          if c not in nbr_colors:
            coloring[i] = c
            break
      return coloring
docs: Returns a greedy vertex coloring as an array of ints.