code: def labels(self):
      # is this only needed for product of groups (intersection)?
      prefix = self.prefix
      uni = self.uni
      sep = self.separator
  
      if uni.ndim > 1:
          label = [
              (prefix + sep.join(["%s"] * len(uni[0]))) % tuple(ii)
              for ii in uni
          ]
      else:
          label = [prefix + "%s" % ii for ii in uni]
      return label
  
imports: from statsmodels.compat.python import lrange, lzip
  import numpy
  import pandas
  import statsmodels.tools.data
  from pandas import Index, MultiIndex
label_desc: Use image node_id 3 for calling the Group obj's underlying member method code with example usage: obj.labels() and returns: label