code: def search_parameters(self, symbol):
      
      if not self.parameters:
        return None
      # Hierarchically lookup the key
      result = None
      if "default" in self.parameters and symbol in self.parameters["default"]:
        result = self.parameters["default"][symbol]
      if self.resolved["ENV_SHORT"] in self.parameters and symbol in self.parameters[self.resolved["ENV_SHORT"]]:
        result = self.parameters[self.resolved["ENV_SHORT"]][symbol]
      # This lookup is redundant when env_short == env, but it's also cheap
      if self.resolved["ENV"] in self.parameters and symbol in self.parameters[self.resolved["ENV"]]:
        result = self.parameters[self.resolved["ENV"]][symbol]
      return result
docs: Hierarchically searches for 'symbol' in the parameters blob if there is one (would have
      been retrieved by 'load()'). Order is: default, <env_short>, <env>
      Returns
        Hierarchically resolved value for 'symbol', or None if a match is not found or there are no parameters