code: def _variable_components(self, variable):
          
          var_list = pd.Series(self.data.variable.unique())
          return var_list[pattern_match(var_list, '{}|*'.format(variable), 0)]
docs: Get all components (sub-categories) of a variable
  
          For `variable='foo'`, return `['foo|bar']`, but don't include
          `'foo|bar|baz'`, which is a sub-sub-category