code: def vstack(tup):
      """
      Stack arrays in sequence vertically (row wise).
  
      This is equivalent to concatenation along the first axis after 1-D arrays
      of shape `(N,)` have been reshaped to `(1,N)`. Rebuilds arrays divided by
      `vsplit`.
  
      This function makes most sense for arrays with up to 3 dimensions. For
      instance, for pixel-data with a height (first axis), width (second axis),
      and r/g/b channels (third axis). The functions `concatenate`, `stack` and
      `block` provide more general stacking and concatenation operations.
  
      Parameters
      ----------
      tup : sequence of ndarrays
          The arrays must have the same shape along all but the first axis.
          1-D arrays must have the same length.
  
      Returns
      -------
      stacked : ndarray
          The array formed by stacking the given arrays, will be at least 2-D.
  
      See Also
      --------
      stack : Join a sequence of arrays along a new axis.
      hstack : Stack arrays in sequence horizontally (column wise).
      dstack : Stack arrays in sequence depth wise (along third dimension).
      concatenate : Join a sequence of arrays along an existing axis.
      vsplit : Split array into a list of multiple sub-arrays vertically.
      block : Assemble arrays from blocks.
  
      Examples
      --------
      >>> a = np.array([1, 2, 3])
      >>> b = np.array([2, 3, 4])
      >>> np.vstack((a,b))
      array([[1, 2, 3],
             [2, 3, 4]])
  
      >>> a = np.array([[1], [2], [3]])
      >>> b = np.array([[2], [3], [4]])
      >>> np.vstack((a,b))
      array([[1],
             [2],
             [3],
             [2],
             [3],
             [4]])
  
      """
      _warn_for_nonsequence(tup)
      return _nx.concatenate([atleast_2d(_m) for _m in tup], 0)
  
imports: from __future__ import division, absolute_import, print_function
  import functools
  import operator
  import types
  import warnings
  from .None import numeric
  from .None import overrides
  from .numeric import array, asanyarray, newaxis
  from .multiarray import normalize_axis_index
label_desc: Use image node_id 10 for calling a global function with example usage: vstack(tup) and returns: _nx