class_docstr: Useful commands
  - run all tests: pytest examples/orderbook_data/example.py
  - run a single test:  pytest -s --pdb --disable-warnings examples/orderbook_data/example.py::TestClass::test_basic01
class_docstr_tok: ["Useful","commands","-","run","all","tests",":","pytest","examples\/orderbook_data\/example.py","-","run","a","single","test",":","pytest","-s","--","pdb","--","disable-warnings","examples\/orderbook_data\/example.py",":",":TestClass",":",":test_basic01"]
code: def test_exp_07_2(self):
      # NOTE: based on on order frequency
      expr7 = (
          lambda funccode, ordercode, time_interval: f"TResample({self.expr7_init(funccode, ordercode, time_interval)}, '1min', 'mean')"
      )
  
      exprs = []
      names = []
      for funccode in ["B", "S"]:
          for ordercode in ["0", "1"]:
              exprs.append(expr7(funccode, ordercode, "3"))
              names.append(
                  self.trans_dict[ordercode]
                  + self.trans_dict[funccode]
                  + "_intensity_3s"
              )
      df = D.features(
          self.stocks_list, fields=exprs, freq="transaction"
      )
      df.columns = names
      print(df)
  
imports: from arctic.arctic import Arctic
  import qlib
  from qlib.data import D
  import unittest
label_desc: Use image node_id 16 for calling the TestClass obj's underlying member method code with example usage: obj.test_exp_07_2() without return types