<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def create_lambda_function(self):
 """Create or update Lambda function."""

        vpc_config = self._vpc_config()

        if self._check_lambda():
            self.update_function_configuration(vpc_config)
        else:
            self.create_function(vpc_config)

        if self._check_lambda_alias():
            self.update_alias()
        else:
            self.create_alias()