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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def cli(env, identifier):
 """Retrieve credentials used for generating an AWS signature. Max of 2."""


    mgr = SoftLayer.ObjectStorageManager(env.client)
    credential_list = mgr.list_credential(identifier)
    table = formatting.Table(['id', 'password', 'username', 'type_name'])

    for credential in credential_list:
        table.add_row([
            credential['id'],
            credential['password'],
            credential['username'],
            credential['type']['name']
        ])

    env.fout(table)