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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 auth_plugins(auth_plugins=None):
 """Authentication plugins. Usage, Add any plugin here that will serve as a rapid means to authenticate to an OpenStack environment. Syntax is as follows: If the subdomain is in the auth url, as is the case with hp, add "%(region)s" to the "os_auth_url" value. The region value from the list of choices will be used as the string replacement. Note that if the `os_prefix` key is added the system will override the authentication body prefix with the string provided. At this time the choices are os_apikey, os_password, os_token. All key entries are optional and should one not be specified with a credential type a `NotImplementedError` will be raised. :param auth_plugins: Additional plugins to add in :type auth_plugins: ``dict`` :returns: ``dict`` """


    __auth_plugins__ = {
        'os_rax_auth': {
            'os_auth_url': 'https://identity.api.rackspacecloud.com/v2.0/'
                           'tokens',
            'os_prefix': {
                'os_apikey': 'RAX-KSKEY:apiKeyCredentials',
                'os_password': 'passwordCredentials'
            },
            'args': {
                'commands': [
                    '--os-rax-auth'
                ],
                'choices': [
                    'dfw',
                    'ord',
                    'iad',
                    'syd',
                    'hkg',
                    'lon'
                ],
                'help': 'Authentication Plugin for Rackspace Cloud'
                        ' env[OS_RAX_AUTH]',
                'default': os.environ.get('OS_RAX_AUTH', None),
                'metavar': '[REGION]'
            }
        },
        'rax_auth_v1': {
            'os_auth_version': 'v1.0',
            'os_auth_url': 'https://identity.api.rackspacecloud.com/v1.0',
            'args': {
                'commands': [
                    '--rax-auth-v1'
                ],
                'action': 'store_true',
                'help': 'Authentication Plugin for Rackspace Cloud V1'
            }
        },
        'os_rax_auth_lon': {
            'os_auth_url': 'https://lon.identity.api.rackspacecloud.com/'
                           'v2.0/tokens',
            'os_prefix': {
                'os_apikey': 'RAX-KSKEY:apiKeyCredentials',
                'os_password': 'passwordCredentials'
            },
            'args': {
                'commands': [
                    '--os-rax-auth-lon'
                ],
                'choices': [
                    'lon'
                ],
                'help': 'Authentication Plugin for Rackspace Cloud'
                        ' env[OS_RAX_AUTH_LON]',
                'default': os.environ.get('OS_RAX_AUTH_LON', None),
                'metavar': '[REGION]'
            }
        },
        'os_hp_auth': {
            'os_auth_url': 'https://%(region)s.identity.hpcloudsvc.com:35357/'
                           'v2.0/tokens',
            'os_prefix': {
                'os_password': 'passwordCredentials'
            },
            'args': {
                'commands': [
                    '--os-hp-auth'
                ],
                'choices': [
                    'region-b.geo-1',
                    'region-a.geo-1'
                ],
                'help': 'Authentication Plugin for HP Cloud'
                        ' env[OS_HP_AUTH]',
                'default': os.environ.get('OS_HP_AUTH', None),
                'metavar': '[REGION]'
            }
        }
    }
    if auth_plugins:
        __auth_plugins__.update(auth_plugins)

    return __auth_plugins__