code: def contrast_all_one(nm):
      """contrast or restriction matrix for all against first comparison
  
      Parameters
      ----------
      nm : int
  
      Returns
      -------
      contr : ndarray, 2d, (nm-1, nm)
         contrast matrix for all against first comparisons
  
      """
      contr = np.column_stack((np.ones(nm - 1), -np.eye(nm - 1)))
      return contr
  
imports: from numpy.testing import assert_equal
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: contrast_all_one(nm) and returns: contr