def cmd_implementation(self, events_lib, top_level_cmd_name, subcmd_name, *args, **kwargs):
event = events_lib.generate_event(top_level_cmd_name, subcmd_name, kwargs)<EOL>click.echo(event)<EOL>return event<EOL>
calls for value substitution in the event json and returns the
customized json as a string

Parameters
----------
events_lib
top_level_cmd_name: string
    the name of the service
subcmd_name: string
    the name of the event under the service
args: tuple
    any arguments passed in before kwargs
kwargs: dict
    the keys and values for substitution in the json
Returns
-------
event: string
    returns the customized event json as a string