'Creates a dictionary to hold document id keys mapped to the
documents as values.'

def __init__(self, url=None, unique_key='_id', auto_commit_interval=None, chunk_size=constants.DEFAULT_MAX_BULK, **kwargs):

    self.unique_key = unique_key
    self.auto_commit_interval = auto_commit_interval
    self.doc_dict = DocumentStore()
    self.url = url
    self.chunk_size = chunk_size
    self.kwargs = kwargs
