code: def subtract(x1, x2):
      if x1.shape != x2.shape:
          raise Exception(
              "subtract expects arguments `x1` and `x2` to have the "
              "same shape, but x1.shape = {}, and x2.shape = {}.".format(
                  x1.shape, x2.shape
              )
          )
      result = DistArray(x1.shape)
      for index in np.ndindex(*result.num_blocks):
          result.object_refs[index] = ra.subtract.remote(
              x1.object_refs[index], x2.object_refs[index]
          )
      return result
  
imports: import numpy
  import ray
  import ray.experimental.array.remote
label_desc: Use image node_id 14 for calling a global function with example usage: subtract(x1, x2) and returns: result