Only use relative imports for functions in the same package.

app/corpora/views.py

@@ -1,13 +1,13 @@
+from app import db
+from app.models import Corpus, CorpusFile
 from app.utils import background_prepare_corpus_file
 from flask import (abort, current_app, flash, redirect, request,
                    render_template, url_for, send_from_directory)
 from flask_login import current_user, login_required
+from werkzeug.utils import secure_filename
 from . import corpora
 from .forms import (AddCorpusFileForm, AddCorpusForm, EditCorpusFileForm,
                     QueryDownloadForm, QueryForm)
-from .. import db
-from ..models import Corpus, CorpusFile
-from werkzeug.utils import secure_filename
 import os
 import threading
 import logging