Traceback (most recent call last):


 "<stdin>", line 1, in <module>


 "/usr/local/totaltrack/lib/python2.7/site-packages/sqlalchemy_utils/__init__.py", line 1, in <module>

from .aggregates import aggregated
# noqa


 "/usr/local/totaltrack/lib/python2.7/site-packages/sqlalchemy_utils/aggregates.py", line 372, in <module>

from .functions.orm import get_column_key


 "/usr/local/totaltrack/lib/python2.7/site-packages/sqlalchemy_utils/functions/__init__.py", line 1, in <module>

from .database import (
# noqa


 "/usr/local/totaltrack/lib/python2.7/site-packages/sqlalchemy_utils/functions/database.py", line 3, in <module>

from collections.abc import Mapping, Sequence
ImportError: No module named abc

Traceback (most recent call last):


 "textrank.py", line 4, in <module>

from summarizer import summarize


 "/home/berserk/textrank/summa/summarizer.py", line 4, in <module>

from preprocessing.textcleaner import clean_text_by_sentences as _clean_text_by_sentences


 "/home/berserk/textrank/summa/preprocessing/textcleaner.py", line 19, in <module>

from summa.syntactic_unit import SyntacticUnit
ImportError: No module named summa.syntactic_unit
