'Creates and returns a new library.
Args:
org (str): the organization that owns the course
library (str): the code/number/name of the library
user_id: id of the user creating the course
fields (dict): Fields to set on the course at initialization - e.g. display_name
kwargs: Any optional arguments understood by a subset of modulestores to customize instantiation
Returns: a LibraryRoot'

@strip_key
def create_library(self, org, library, user_id, fields, **kwargs):

    lib_key = LibraryLocator(org=org, library=library)
    if (lib_key in self.mappings):
        raise DuplicateCourseError(lib_key, lib_key)
    store = self._verify_modulestore_support(None, 'create_library')
    library = store.create_library(org, library, user_id, fields, **kwargs)
    self.mappings[lib_key] = store
    return library
