class_docstr: A temporary Probability Space for the Compound Distribution. After
  Marginalization, this returns the corresponding Probability Space of the
  parent distribution.
code: def symbol(self):
      return self.args[0]
  
imports: from sympy.concrete.summations import Sum
  from sympy.core.basic import Basic
  from sympy.core.function import Lambda
  from sympy.core.symbol import Dummy
  from sympy.integrals.integrals import Integral
  from sympy.stats.rv import NamedArgsMixin, random_symbols, _symbol_converter, PSpace, RandomSymbol, is_random, Distribution
  from sympy.stats.crv import ContinuousDistribution, SingleContinuousPSpace
  from sympy.stats.drv import DiscreteDistribution, SingleDiscretePSpace
  from sympy.stats.frv import SingleFiniteDistribution, SingleFinitePSpace
  from sympy.stats.crv_types import ContinuousDistributionHandmade
  from sympy.stats.drv_types import DiscreteDistributionHandmade
  from sympy.stats.frv_types import FiniteDistributionHandmade
label_desc: Use image node_id 3 for calling the CompoundPSpace obj's underlying member method code with example usage: obj.symbol() and returns: self