<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def format_link_json(self):
 """Convert a Link object to json format."""

        link_json = {}
        link_json['trace_id'] = self.trace_id
        link_json['span_id'] = self.span_id
        link_json['type'] = self.type

        if self.attributes is not None:
            link_json['attributes'] = self.attributes

        return link_json