def collection_to_df(collection):
return pd.concat([record.series for record in collection], axis=<NUM_LIT:1>).T<EOL>
Converts a collection back into a pandas DataFrame

parameters
----------
collection : list
    list of Record objects where each Record represents one row from a dataframe

Returns
-------
df : pandas.DataFrame
    DataFrame of length=len(collection) where each row represents one Record