class_docstr: FrequencyEncoder
  Conversion of category into frequencies.
  Parameters
      ----------
  cols : list of categorical features.
  drop_invariant : not used
docstr: Description of __init__
  
  Args:
      cols=None (undefined): columns in dataset
      drop_invariant=None (undefined): not used
docstr_tok: ["Description","of","__init__","Args",":","cols=None","(","undefined",")",":","columns","in","dataset","drop_invariant=None","(","undefined",")",":","not","used"]
code: def __init__(self, cols=None, drop_invariant=None):
      """
      Description of __init__
  
      Args:
          cols=None (undefined): columns in dataset
          drop_invariant=None (undefined): not used
  
      """
      self.cols = cols
      self.counts_dict = None
  
imports: import pandas
  import numpy
label_desc: Use image node_id 1 to create a new FrequencyEncoder object  with example: obj = FrequencyEncoder(cols, drop_invariant)