class_docstr: This class represents an abstract partition.
  
  A partition is a set of disjoint sets whose union equals a given set.
  
  See Also
  ========
  
  sympy.utilities.iterables.partitions,
  sympy.utilities.iterables.multiset_partitions
docstr: Return partition as a sorted list of lists.
  
  Examples
  ========
  
  >>> from sympy.combinatorics import Partition
  >>> Partition([1], [2, 3]).partition
  [[1], [2, 3]]
code: def partition(self):
      """Return partition as a sorted list of lists.
  
      Examples
      ========
  
      >>> from sympy.combinatorics import Partition
      >>> Partition([1], [2, 3]).partition
      [[1], [2, 3]]
      """
      if self._partition is None:
          self._partition = sorted(
              [sorted(p, key=default_sort_key) for p in self.args]
          )
      return self._partition
  
imports: from sympy.core import Basic, Dict, sympify, Tuple
  from sympy.core.numbers import Integer
  from sympy.core.sorting import default_sort_key
  from sympy.core.sympify import _sympify
  from sympy.functions.combinatorial.numbers import bell
  from sympy.matrices import zeros
  from sympy.sets.sets import FiniteSet, Union
  from sympy.utilities.iterables import flatten, group
  from sympy.utilities.misc import as_int
  from collections import defaultdict
label_desc: Use image node_id 3 for calling the Partition obj's underlying member method code with example usage: obj.partition() and returns: self