class_docstr: Use this context manager to automatically start and close a database session
  
  Examples:
      >>> with DBContextManager('ProjectFolder') as session:
      >>>     # Do stuff with session
class_docstr_tok: ["Use","this","context","manager","to","automatically","start","and","close","a","database","session","Examples",":",">",">",">","with","DBContextManager","(","'ProjectFolder","'",")","as","session",":",">",">",">","#","Do","stuff","with","session"]
code: def __exit__(self, exc_type, exc_val, exc_tb):
      if hasattr(self, "session"):
          if exc_type is not None:
              self.session.rollback()
          self.session.close()
      return False
  
imports: from __future__ import absolute_import, print_function, division, unicode_literals
  import imp
  import sys
  import os
  import hashlib
  import json
  import numpy
  from sqlalchemy import create_engine
  from sqlalchemy.orm import Session
  from six import exec_, iteritems
  from sklearn import datasets
  from sklearn import model_selection
  from xcessiv import app, exceptions
label_desc: Use image node_id 3 for calling the DBContextManager obj's underlying member method code with example usage: obj.__exit__(exc_type, exc_val, exc_tb) and returns: False