code: def assert_all_empty(self, dfs):
      for k, v in dfs.items():
          assert_equal(
              len(v), 0, msg="%s dataframe should be empty" % k
          )
  
imports: import logbook
  import numpy
  import pandas
  from zipline.data.adjustments import SQLiteAdjustmentReader, SQLiteAdjustmentWriter
  from zipline.data.in_memory_daily_bars import InMemoryDailyBarReader
  from zipline.testing import parameter_space
  from zipline.testing.predicates import assert_equal
  from zipline.testing.fixtures import WithInstanceTmpDir, WithTradingCalendars, WithLogger, ZiplineTestCase
label_desc: Use image node_id 8 for calling the TestSQLiteAdjustmentsWriter obj's underlying member method code with example usage: obj.assert_all_empty(dfs) without return types