code: def let_statement(u):
      
      if u.__class__ is node.let:
          if (u.ret.__class__ is node.ident and
              u.args.__class__ is node.matrix):
              u.args = node.funcall(func_expr=node.ident("matlabarray"),
                                    args=node.expr_list([u.args]))
docs: If LHS is a plain variable, and RHS is a matrix
      enclosed in square brackets, replace the matrix
      expr with a funcall.