In ep7 classifier.fit() raises "IndexError: invalid index to scalar variable"

[mbaytas]

Full disclosure: I'm not using the Docker image, but working in my own environment on a Mac (10.12.2) with Python 2.7 (via Homebrew) and Tensorflow 0.12.1.

I'm going through the code for Episode 7, where I get an "IndexError: invalid index to scalar variable" on the line classifier.fit(data, labels, batch_size=100, steps=1000). Here's my code in full (exactly same as the tutorial):

import numpy as np
import matplotlib.pyplot as plt
import tensorflow as tf
learn = tf.contrib.learn

mnist = learn.datasets.load_dataset('mnist')
data = mnist.train.images
labels = np.asarray(mnist.train.labels, dtype=np.int32)
test_data = mnist.test.images
test_labels = np.asarray(mnist.test.labels, dtype=np.int32)

max_examples = 10000
data = data[:max_examples]
labels = labels[max_examples]

feature_columns = learn.infer_real_valued_columns_from_input(data)
classifier = learn.LinearClassifier(feature_columns=feature_columns, n_classes=10)
classifier.fit(data, labels, batch_size=100, steps=1000)

Here's the complete error:

Traceback (most recent call last):
  File "/Users/mbaytas/Dropbox/works-code/ml-studies/google-recipes/ep7-mnist/ep7.py", line 38, in <module>
    classifier.fit(data, labels, batch_size=100, steps=1000)
  File "/usr/local/lib/python2.7/site-packages/tensorflow/contrib/learn/python/learn/estimators/linear.py", line 446, in fit
    max_steps=max_steps)
  File "/usr/local/lib/python2.7/site-packages/tensorflow/python/util/deprecation.py", line 191, in new_func
    return func(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/tensorflow/contrib/learn/python/learn/estimators/estimator.py", line 355, in fit
    max_steps=max_steps)
  File "/usr/local/lib/python2.7/site-packages/tensorflow/contrib/learn/python/learn/estimators/estimator.py", line 733, in _train_model
    max_steps=max_steps)
  File "/usr/local/lib/python2.7/site-packages/tensorflow/contrib/learn/python/learn/graph_actions.py", line 300, in _monitored_train
    _, loss = super_sess.run([train_op, loss_op], feed_fn() if feed_fn else
  File "/usr/local/lib/python2.7/site-packages/tensorflow/contrib/learn/python/learn/learn_io/data_feeder.py", line 407, in _feed_dict_fn
    out[i] = _access(self._y, sample)
  File "/usr/local/lib/python2.7/site-packages/tensorflow/contrib/learn/python/learn/learn_io/data_feeder.py", line 208, in _access
    return data[iloc]
IndexError: invalid index to scalar variable.