code: def _P(A):
      """Twice the number of concordant pairs, excluding ties."""
      # See `somersd` References [2] bottom of page 309
      m, n = A.shape
      count = 0
      for i in range(m):
          for j in range(n):
              count += A[i, j] * _Aij(A, i, j)
      return count
  
label_desc: Use image node_id 3 for calling a global function with example usage: _P(A) and returns: count