<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_router(self, context, router):
 """Creates a router on Arista Switch. Deals with multiple configurations - such as Router per VRF, a router in default VRF, Virtual Router in MLAG configurations """

        if router:
            router_name = self._arista_router_name(router['id'],
                                                   router['name'])

            hashed = hashlib.sha256(router_name.encode('utf-8'))
            rdm = str(int(hashed.hexdigest(), 16) % 65536)

            mlag_peer_failed = False
            for s in self._servers:
                try:
                    self.create_router_on_eos(router_name, rdm, s)
                    mlag_peer_failed = False
                except Exception:
                    if self._mlag_configured and not mlag_peer_failed:
                        # In paied switch, it is OK to fail on one switch
                        mlag_peer_failed = True
                    else:
                        msg = (_('Failed to create router %s on EOS') %
                               router_name)
                        LOG.exception(msg)
                        raise arista_exc.AristaServicePluginRpcError(msg=msg)