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 collections import namedtuple
  from statsmodels.compat.python import lzip, lrange
  import copy
  import math
  import numpy
  from numpy.testing import assert_almost_equal, assert_equal
  from scipy import stats, interpolate
  from statsmodels.iolib.table import SimpleTable
  from statsmodels.stats.multitest import multipletests, _ecdf, fdrcorrection, fdrcorrection_twostage
  from statsmodels.graphics import utils
  from statsmodels.tools.sm_exceptions import ValueWarning
label_desc: Use image node_id 24 for calling a global function with example usage: contrast_all_one(nm) and returns: contr