code: def get_composition(self):
          '''Get composition of output structure
          
          Returns:
              String - Composition based on output structure
          '''
          strc = self.get_output_structure()
          counts = Counter(strc.get_chemical_symbols())
          return ''.join(k if counts[k]==1 else '%s%d'%(k,counts[k]) \
                  for k in sorted(counts)f get_composition(self):
          '''Get composition of output structure
          
          Returns:
              String - Composition based on output structure
          '''
          strc = self.get_output_structure()
          counts = Counter(strc.get_chemical_symbols())
          return ''.join(k if counts[k]==1 else '%s%d'%(k,counts[k]) \
                  for k in sorted(counts))
docs: Get composition of output structure
          
          Returns:
              String - Composition based on output structure