duplicate key error when using the api to deploy the same charm more than once

[Kapil Thangavelu]

  File "/home/kapil/canonical/jujuclient/jujuclient.py", line 494, in deploy
    "ToMachineSpec": machine_spec}})
  File "/home/kapil/canonical/jujuclient/jujuclient.py", line 145, in _rpc
    raise EnvError(result)
EnvError: <Env Error - Details:
 { u'Error': u'cannot add charm: cannot add charm "cs:precise/postgresql-52": E11000 duplicate key error index: juju.charms.$_id_ dup key: { : "cs:precise/postgresql-52" }',
    u'RequestId': 1,
    u'Response': { }}

different service names