If several services have the same names like this:
+------ ------- ------- ------- ------- +------ ------- +------ ------- ---+
| ID | Name | Type |
+------ ------- ------- ------- ------- +------ ------- +------ ------- ---+
| 148f5e8cc6154fa c92f6031e8040ae e0 | ceilometer | metering |
| 186fd71836d745d e8c84f959d34639 af | glance | image |
| 18a0e5976899483 9840af7ed125922 74 | nova | syj |
| 42c41632597d4d3 fa2ad042b5ed0e8 1a | nova | compute |
| 455680b30d3f4af 4a63bb9722828bc 30 | cinder | volume |
| 67c7ada5f4c24c2 f94e6368ac9ae11 00 | None | syj |
| 79d150b92f4b4f7 dba64ec419f9161 19 | neutron | syj |
| 7dc9bd2115234ae 9bac0ad430b900c ca | nova_legacy | compute_legacy |
| 8df25ac9adcd478 488cb4ee004e577 37 | keystone | identity |
| 98bcf89fbcbf44b 9a155a0fec38f6c 42 | cinderv2 | volumev2 |
| ed7d55b2d415417 e9d13e65035dd66 94 | neutron | network |
| f94c3860ebb7478 99f6e002ce766ca 87 | cinderv3 | volumev3 |
+------ ------- ------- ------- ------- +------ ------- +------ ------- ---+

``service show nova`` raises a wrong exception:
No service with a type, name or ID of 'nova' exists.
Actually, it should be:
Multiple service matches found for 'nova', use an ID to be more specific.