hi,I start to learn to study the crab using python ,but I come across some problems, my example's code is

author = 'Cookie'
from scikits.crab import datasets
movies = datasets.load_sample_movies()
songs = datasets.load_sample_songs()

print(movies.data)

print(songs)
from scikits.crab.models import MatrixPreferenceDataModel
#Build the model
model = MatrixPreferenceDataModel(movies.data)
from scikits.crab.metrics import pearson_correlation
from scikits.crab.similarities import UserSimilarity

Build the similarity

similarity = UserSimilarity(model, pearson_correlation)

from scikits.crab.recommenders.knn import UserBasedRecommender

problems:
Traceback (most recent call last):
File "D:/Rail/jx/Python/project1/Crab.py", line 16, in
from scikits.crab.recommenders.knn import UserBasedRecommender
File "D:\Program Files (x86)\Python27\lib\site-packages\scikits\crab\recommenders\knn__init__.py", line 1, in
from .classes import ItemBasedRecommender, UserBasedRecommender
File "D:\Program Files (x86)\Python27\lib\site-packages\scikits\crab\recommenders\knn\classes.py", line 17, in
from base import ItemRecommender, UserRecommender
File "D:\Program Files (x86)\Python27\lib\site-packages\scikits\crab\recommenders\knn\base.py", line 17, in
from ..base import MemoryBasedRecommender
File "D:\Program Files (x86)\Python27\lib\site-packages\scikits\crab\recommenders\base.py", line 17, in
from ..base import BaseRecommender
File "D:\Program Files (x86)\Python27\lib\site-packages\scikits\crab\base.py", line 11, in
from scikits.learn.base import BaseEstimator
ImportError: No module named learn.base

I had installed the packages:Python 2.7.9, numpy-MKL-1.8.0.win-amd64-py2.7,scipy-0.15.1-cp27-none-win_amd64,matplotlib-1.4.3.win-amd64-py2.7,scikit-learn-0.16.1.win-amd64-py2.7,thank you very much.