code: def __init__(self, rank=None):
      self.root = FPNode(None)
      self.nodes = collections.defaultdict(list)
      self.cond_items = []
      self.rank = rank
  
file_path: mlxtend/mlxtend/frequent_patterns/fpcommon.py
imports: import collections
  import warnings
  import numpy
  import pandas
  from pandas import __version__
label_desc: Use image node_id 1 to create a new FPTree object from inherited base classes: object with example: obj = FPTree(rank)