def get_firewall_rule(self, datacenter_id,<EOL>server_id, nic_id, firewall_rule_id):
response = self._perform_request(<EOL>'<STR_LIT>' % (<EOL>datacenter_id,<EOL>server_id,<EOL>nic_id,<EOL>firewall_rule_id))<EOL>return response<EOL>
Retrieves a single firewall rule by ID.

:param      datacenter_id: The unique ID of the data center.
:type       datacenter_id: ``str``

:param      server_id: The unique ID of the server.
:type       server_id: ``str``

:param      nic_id: The unique ID of the NIC.
:type       nic_id: ``str``

:param      firewall_rule_id: The unique ID of the firewall rule.
:type       firewall_rule_id: ``str``