code: def _stmt_list(self, stmts, indent=True):
          
          stmts = "\n".join(nstr for nstr in [n.accept(self) for n in stmts] if nstr)
          if indent:
              return self.indent + stmts.replace("\n", "\n" + self.indent)
  
          return stmts
docs: return a list of nodes to string