code: def trisolve(U, b, uplo='U', transa='N', alpha=1., inplace=False):
      
      if inplace:
          x = b
      else:
          x = b.copy('F')
      if U.shape[0] == 0:
          raise ValueError('Attempted to solve zero-rank triangular system')
      dtrsm_wrap(a=U, b=x, side='L', uplo=uplo, transa=transa, alpha=alpha)
      return x
docs: x = trisolve(U,b, uplo='U')
  
  
      Solves U x = b, where U is upper triangular if uplo='U'
      or lower triangular if uplo = 'L'.
  
  
      If a degenerate column is found, an error is raised.