code: def length(self):
      return len(self.pcgs)
  
imports: from sympy.ntheory.primetest import isprime
  from sympy.combinatorics.perm_groups import PermutationGroup
  from sympy.printing.defaults import DefaultPrinting
  from sympy.combinatorics.free_groups import free_group
label_desc: Use image node_id 3 for calling the PolycyclicGroup obj's underlying member method code with example usage: obj.length() and returns: len