<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def ProcessLegacyClient(self, ping, client):
 """Update counters for system, version and release attributes."""

    labels = self._GetClientLabelsList(client)
    system = client.Get(client.Schema.SYSTEM, "Unknown")
    uname = client.Get(client.Schema.UNAME, "Unknown")

    self._Process(labels, ping, system, uname)