code: def trsm(self,B,trans='N'):
          r
          
          if trans=='N':
              cp.trsm(self._L0,B)
              pftrsm(self._V,self._L,self._B,B,trans='N')
          elif trans=='T':
              pftrsm(self._V,self._L,self._B,B,trans='T')
              cp.trsm(self._L0,B,trans='T')
          elif type(trans) is str:
              raise ValueError("trans must be 'N' or 'T'")
          else:
              raise TypeError("trans must be 'N' or 'T'")
          return
docs: r"""
          Solves a triangular system of equations with multiple righthand
          sides. Computes
  
          .. math::
  
              B &:= L^{-1} B  \text{ if trans is 'N'}
  
             B &:= L^{-T} B  \text{ if trans is 'T'}