docs: def multicolumn_store_with_uncompressed_write(mongo_server):
      """
      The database state created by this fixture is equivalent to the following operations using arctic 1.40
      or previous:
  
          arctic.initialize_library('arctic_test.TEST', m.VERSION_STORE, segment='month')
          library = arctic.get_library('arctic_test.TEST')
          df = pd.DataFrame([[1,2], [3,4]], index=['x','y'], columns=[['a','w'], ['a','v']])
          library.write('pandas', df)
  
      different from newer versions, the last write creates a uncompressed chunk.
      """
      mongo_server.api.drop_database('arctic_test')
  
      library_name = 'arctic_test.TEST'
      arctic = m.Arctic(mongo_host=mongo_server.api)
      arctic.initialize_library(library_name, m.VERSION_STORE, segment='month')
  
      db = mongo_server.api.arctic_test
      db.TEST.insert_many([
          {
              'parent': [bson.ObjectId('5ad0dc065c911d1188b512d8')],
              'data': bson.Binary(b'\x11\x00\x00\x002x\x01\x00\x01\x00\x80\x02\x00\x00\x00\x00\x00\x00\x00', 0),
              'symbol': 'pandas',
              'sha': bson.Binary(b'\xaa\\`\x0e\xc2D-\xc1_\xf7\xfd\x12\xfa\xd2\x17\x05`\x00\x98\xe2', 0),
              'compressed': True,
              '_id': bson.ObjectId('5ad0dc067934ecad404070be'),
              'segment': 0
          },
          {
              'parent': [bson.ObjectId('5ad0dc065c911d1188b512d8')],
              'data': bson.Binary(b'y\x03\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00', 0),
              'symbol': 'pandas',
              'sha': bson.Binary(b'\xfe=WQ\xb5\xfdL\xb7\xcavd\x85o\x04]\x04\xdb\xa8]3', 0),
              'compressed': False,
              '_id': bson.ObjectId('5ad0dc077934ecad404070bf'),
              'segment': 1
          }
      ])
      db.TEST.ARCTIC.update_one({"_id": "ARCTIC_META"}, {"$set": {"_id": "ARCTIC_META", "TYPE": "VersionStore", "QUOTA": 10737418240}})
      db.TEST.version_nums.insert_one({'symbol': 'pandas', '_id': bson.ObjectId('5ad0dc067934ecad404070bd'), 'version': 2})
      db.TEST.versions.insert_many([
          {
              'append_count': 0,
              'dtype_metadata': {
                  'index': ['index'],
                  'columns': ["('a', 'a')", "('w', 'v')"]
              },
              'segment_count': 1,
              'dtype': '[(\'index\', \'S1\'), ("(\'a\', \'a\')", \'<i8\'), ("(\'w\', \'v\')", \'<i8\')]',
              'symbol': 'pandas',
              'up_to': 1,
              'metadata': None,
              'sha': bson.Binary(b'\xf2\x15h\x9d\x925\x95\xa5\x0e\x95J\xc4x\xfc\xfc\xd5\x80\xe0\x1d\xef', 0),
              'shape': [-1],
              'version': 1,
              'base_sha': bson.Binary(b'\xf2\x15h\x9d\x925\x95\xa5\x0e\x95J\xc4x\xfc\xfc\xd5\x80\xe0\x1d\xef', 0),
              '_id': bson.ObjectId('5ad0dc065c911d1188b512d8'),
              'type': 'pandasdf',
              'append_size': 0
          },
          {
              'append_count': 1,
              'dtype_metadata': {
                  'index': ['index'],
                  'columns': ["('a', 'a')", "('w', 'v')"]
              },
              'segment_count': 2,
              'sha': bson.Binary(b'1\x83[ZO\xec\x080D\x80f\xe4@\xe4\xd3\x94yG\xe2\x08', 0),
              'dtype': '[(\'index\', \'S1\'), ("(\'a\', \'a\')", \'<i8\'), ("(\'w\', \'v\')", \'<i8\')]',
              'symbol': 'pandas',
              'up_to': 2,
              'metadata': None,
              'base_version_id': bson.ObjectId('5ad0dc065c911d1188b512d8'),
              'shape': [-1],
              'version': 2,
              'base_sha': bson.Binary(b'\xf2\x15h\x9d\x925\x95\xa5\x0e\x95J\xc4x\xfc\xfc\xd5\x80\xe0\x1d\xef', 0),
              '_id': bson.ObjectId('5ad0dc075c911d1188b512d9'),
              'type': 'pandasdf',
              'append_size': 17
          }
      ])
  
      return {'symbol': 'pandas', 'store': arctic.get_library('arctic_test.TEST')}