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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 _create_identity(id_type=None, username=None, password=None, tenant_id=None, tenant_name=None, api_key=None, verify_ssl=None, return_context=False):
 """ Creates an instance of the current identity_class and assigns it to the module-level name 'identity' by default. If 'return_context' is True, the module-level 'identity' is untouched, and instead the instance is returned. """

    if id_type:
        cls = _import_identity(id_type)
    else:
        cls = settings.get("identity_class")
    if not cls:
        raise exc.IdentityClassNotDefined("No identity class has "
                "been defined for the current environment.")
    if verify_ssl is None:
        verify_ssl = get_setting("verify_ssl")
    context = cls(username=username, password=password, tenant_id=tenant_id,
            tenant_name=tenant_name, api_key=api_key, verify_ssl=verify_ssl)
    if return_context:
        return context
    else:
        global identity
        identity = context