code: def _atleast_nd(a, ndim):
      # Ensures `a` has at least `ndim` dimensions by prepending
      # ones to `a.shape` as necessary
      return array(a, ndmin=ndim, copy=False)
  
file_path: mars/mars/tensor/merge/block.py
imports: import functools
  import itertools
  import operator
  import numpy
  from ..datasource.empty import empty
  from ..datasource.array import array
label_desc: Use image node_id 3 for calling a global function with example usage: _atleast_nd(a, ndim) and returns: array