code: def test_invalid_suffixtype(self):
      # If all stubs names end with a string, but a numeric suffix is
      # assumed,  an empty data frame is returned
      df = DataFrame(
          {
              "Aone": [1.0, 2.0],
              "Atwo": [3.0, 4.0],
              "Bone": [5.0, 6.0],
              "X": ["X1", "X2"],
          }
      )
      df["id"] = df.index
      exp_data = {
          "X": "",
          "Aone": [],
          "Atwo": [],
          "Bone": [],
          "id": [],
          "year": [],
          "A": [],
          "B": [],
      }
      expected = DataFrame(exp_data).astype({"year": np.int64})
  
      expected = expected.set_index(["id", "year"])
      expected.index = expected.index.set_levels([0, 1], level=0)
      result = wide_to_long(df, ["A", "B"], i="id", j="year")
      tm.assert_frame_equal(
          result.sort_index(axis=1), expected.sort_index(axis=1)
      )
  
imports: import re
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, date_range, lreshape, melt, wide_to_long
  import pandas._testing
label_desc: Use image node_id 9 for calling the TestWideToLong obj's underlying member method code with example usage: obj.test_invalid_suffixtype() without return types