Details for the main method:
knn_impute_turi(sframe,k):
'''
This method will fill all the missing values in the SFrame using
KNN. The whole process is designed using Turi Create to handel large
dataset that cannot be fit into RAM.
sframe: a turicreate.SFrame object
k: K nearest neighbors for KNN
return: sframe without any missing value
NOTICE: The whole set is required to have at least one column without
any missing value. However, it is recommanded that more than
half of the columns should be without any missing value.
NOTICE: The order of the rows is preserved but the order of columns is not.
NOTICE: Please do not include any feature that is identical for each entry,
ie. ID_NUMBERS...
'''
For information about Turi Create, visit: https://github.com/apple/turicreate