code: def _rechunk_cols_into_one(cls, x, y):
      y_is_x = y is x
      if x.chunk_shape[1] != 1 or y.chunk_shape[1] != 1:
          if has_unknown_shape([x, y]):
              yield
  
          x = yield from recursive_tile(x.rechunk({1: x.shape[1]}))
          if y_is_x:
              y = x
          else:
              y = yield from recursive_tile(y.rechunk({1: y.shape[1]}))
  
      return x, y
  
file_path: mars/mars/learn/metrics/pairwise/core.py
imports: import itertools
  import numpy
  from ....core import recursive_tile
  from ....serialization.serializables import Int64Field
  from ....tensor.operands import TensorOperand, TensorOperandMixin
  from ....tensor import tensor
  from ....utils import has_unknown_shape
  from ...utils import check_array
label_desc: Use image node_id 5 for calling the PairwiseDistances obj's underlying member method code with example usage: obj._rechunk_cols_into_one(cls, x, y) and returns: x,  y