docs: def db_putHex(self, db_name, key, value):
          """https://github.com/ethereum/wiki/wiki/JSON-RPC#db_puthex
  
          DEPRECATED
          """
          warnings.warn('deprecated', DeprecationWarning)
          if not value.startswith('0x'):
              value = add_0x(value)
          return (yield from self.rpc_call('db_putHex', [db_name, key, value]))