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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 list_users(profile="splunk"):
    '''
    List all users in the splunk DB

    CLI Example:

        salt myminion splunk.list_users
    '''

    config = __salt__['config.option'](profile)
    key = "splunk.users.{0}".format(
        config.get('host')
    )

    if key not in __context__:
        _populate_cache(profile)

    return __context__[key]