code: def manhattan(x, y):
      r"""Manhattan, taxicab, or l1 distance.
  
      .. math::
          D(x, y) = \sum_i |x_i - y_i|
      """
      result = 0.0
      for i in range(x.shape[0]):
          result += np.abs(x[i] - y[i])
  
      return result
  
imports: import numpy
  import numba
  from pynndescent.optimal_transport import allocate_graph_structures, initialize_graph_structures, initialize_supply, initialize_cost, network_simplex_core, total_cost, ProblemStatus, sinkhorn_transport_plan
label_desc: Use image node_id 4 for calling a global function with example usage: manhattan(x, y) and returns: result