Bug in mimic_direct_extract.py: 'Series' object has no attribute 'columns' on line 973

[amakelov]

Running

python3 mimic_direct_extract.py 

fails with the following traceback:

Traceback (most recent call last):
  File "mimic_direct_extract.py", line 973, in <module>
    if N is not None: print("Notes", N.shape, N.index.names, N.columns.names)
  File "/afs/csail.mit.edu/u/a/amakelov/.conda/envs/mimic_data_extraction/lib/python3.6/site-packages/pandas/core/generic.py", line 5063, in __getattr__
    return object.__getattribute__(self, name)
AttributeError: 'Series' object has no attribute 'columns'

I believe this is not due to something wrong with setting up the database or the materialized views. Rather, it seems that something went wrong with the internal logic of the script (seems like the script expects N to be a dataframe?).