code: def solve_sparse(self, B):
          
          B = B.tocsc()
          cols = list()
          for j in xrange(B.shape[1]):
              col = self.solve(B[:,j])
              cols.append(csc_matrix(col))
          return hstack(cols)
docs: Solve linear equation of the form A X = B. Where B and X are sparse matrices.
  
          Parameters
          ----------
          B : any scipy.sparse matrix
              Right-hand side of the matrix equation.
              Note: it will be converted to csc_matrix via `.tocsc()`.
  
          Returns
          -------
          X : csc_matrix
              Solution to the matrix equation as a csc_matrix