code: def column_or_1d(y, *, warn=False):
      shape = y.shape
      if len(shape) == 2 and shape[1] == 1:
          y = ivy.reshape(y, (-1,))
      elif len(shape) > 2:
          raise ValueError("y should be a 1d array or a column vector")
      return y
  
imports: import ivy
  from ivy.functional.frontends.numpy.func_wrapper import to_ivy_arrays_and_back
  from ivy.func_wrapper import with_unsupported_dtypes
label_desc: Use image node_id 2 for calling a global function with example usage: column_or_1d(y) and returns: y