code: def edge_average(a):
      "Return the mean value around the edge of an array."
  
      if len(np.ravel(a)) < 2:
          return float(a[0])
      else:
          top_edge = a[0]
          bottom_edge = a[-1]
          left_edge = a[1:-1,0]
          right_edge = a[1:-1,-1]
  
          edge_sum = np.sum(top_edge) + np.sum(bottom_edge) + np.sum(left_edge) + np.sum(right_edge)
          num_values = len(top_edge)+len(bottom_edge)+len(left_edge)+len(right_edge)
  
          return float(edge_sum)/num_valuef edge_average(a):
      "Return the mean value around the edge of an array."
  
      if len(np.ravel(a)) < 2:
          return float(a[0])
      else:
          top_edge = a[0]
          bottom_edge = a[-1]
          left_edge = a[1:-1,0]
          right_edge = a[1:-1,-1]
  
          edge_sum = np.sum(top_edge) + np.sum(bottom_edge) + np.sum(left_edge) + np.sum(right_edge)
          num_values = len(top_edge)+len(bottom_edge)+len(left_edge)+len(right_edge)
  
          return float(edge_sum)/num_values
docs: Return the mean value around the edge of an array.