Answer Happy

Implement a function concat(df) that will take as
input the original dataframe and will return it with an additional
column called full_text, which will
concatenate title and selftext columns, but
with the following restrictions:
Next,
implement function enrich_posts(df) that
will take as input the original dataframe and will return it
with two additional
columns: enriched_title and enriched_selftext. These
columns will contain tokenized, pos-tagged and lower cased versions
of the original text. You must implement them in this
order, because the pos tagger uses casing information.