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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 pnum_to_group(mesh_shape, group_dims, pnum):
 """Group number for grouped allreduce. Args: mesh_shape: a Shape group_dims: a list of integers (the dimensions reduced over) pnum: an integer Returns: an integer """

  coord = pnum_to_processor_coordinates(mesh_shape, pnum)
  remaining_shape = Shape(
      [d for i, d in enumerate(mesh_shape) if i not in group_dims])
  remaining_coord = [d for i, d in enumerate(coord) if i not in group_dims]
  return processor_coordinates_to_pnum(remaining_shape, remaining_coord)