code: def setup(self):
      nyrs = 20
      nidvars = 20
      N = 5000
      self.letters = list("ABCD")
      yrvars = [
          letter + str(num)
          for letter, num in product(self.letters, range(1, nyrs + 1))
      ]
      columns = [str(i) for i in range(nidvars)] + yrvars
      self.df = DataFrame(
          np.random.randn(N, nidvars + len(yrvars)), columns=columns
      )
      self.df["id"] = self.df.index
  
imports: from itertools import product
  import string
  import numpy
  import pandas
  from pandas import DataFrame, MultiIndex, date_range, melt, wide_to_long
  from pandas.api.types import CategoricalDtype
  from .pandas_vb_common import setup
label_desc: Use image node_id 1 for calling the WideToLong obj's underlying member method code with example usage: obj.setup() without return types