class_docstr: Compare histogram to previous rolling normalized histograms
class_docstr_tok: ["Compare","histogram","to","previous","rolling","normalized","histograms"]
code: def transform(self, datastore):
      self.logger.info(
          f'Comparing "{self.read_key}" with relative mean of {self.window} previous histogram(s).'
      )
      return super().transform(datastore)
  
imports: import numpy
  import pandas
  from popmon.analysis.apply_func import ApplyFunc
  from popmon.analysis.functions import expand_norm_hist_mean_cov, expanding_hist, hist_sum, normalized_hist_mean_cov, relative_chi_squared, roll_norm_hist_mean_cov, rolling_hist
  from popmon.analysis.hist_numpy import check_similar_hists, get_consistent_numpy_entries, get_consistent_numpy_ndgrids
  from popmon.base import Pipeline
  from popmon.hist.hist_utils import COMMON_HIST_TYPES, is_numeric
label_desc: Use image node_id 2 for calling the RollingNormHistComparer obj's underlying member method code with example usage: obj.transform(datastore) and returns: super