<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def process(self, plugin, context, instance=None, action=None):
 """Transmit a `process` request to host Arguments: plugin (PluginProxy):
 Plug-in to process context (ContextProxy):
 Filtered context instance (InstanceProxy, optional):
 Instance to process action (str, optional):
 Action to process """


        plugin = plugin.to_json()
        instance = instance.to_json() if instance is not None else None
        return self._dispatch("process", args=[plugin, instance, action])