text: 
  def getting(item, element='atom', indices=None, ids=None, **kwargs):
  
      result=[]
      args = [ii for ii in kwargs if kwargs[ii]]
  
      if element=='atom':
  
          for option in args:
              if option=='n_atoms':
                  raise NotImplementedError
              elif option in ['atom_name', 'name']:
                  raise NotImplementedError
              elif option in ['atom_index', 'index']:
                  raise NotImplementedError
              elif option in ['atom_id', 'id']:
                  raise NotImplementedError
              elif option in ['atom_type', 'type']:
                  raise NotImplementedError
              elif option=='n_residues':
                  raise NotImplementedError
              elif option=='residue_name':
                  raise NotImplementedError
              elif option=='residue_index':
                  raise NotImplementedError
              elif option=='residue_id':
                  raise NotImplementedError
              elif option=='chain_index':
                  raise NotImplementedError
              elif option=='chain_id':
                  raise NotImplementedError
              elif option=='n_frames':
                  raise NotImplementedError
              elif option=='n_chains':
                  raise NotImplementedError
              elif option=='n_molecules':
                  raise NotImplementedError
              elif option=='n_aminoacids':
                  raise NotImplementedError
              elif option=='n_nucleotides':
                  raise NotImplementedError
              elif option=='n_waters':
                  raise NotImplementedError
              elif option=='n_ions':
                  raise NotImplementedError
              elif option=='mass':
                  raise NotImplementedError
              elif option=='net_mass':
                  raise NotImplementedError
              elif option=='charge':
                  raise NotImplementedError
              elif option=='net_charge':
                  raise NotImplementedError
              elif option=='n_degrees_of_freedom':
                  raise NotImplementedError
              elif option=='bonded_atoms':
                  raise NotImplementedError
              elif option=='bonds':
                  raise NotImplementedError
              elif option=='graph':
                  raise NotImplementedError
              elif option=='molecules':
                  raise NotImplementedError
              elif option=='molecule_type':
                  raise NotImplementedError
              elif option=='coordinates':
                  tmp_unit = item.positions.unit
                  tmp_positions = [item.positions[ii]._value for ii in indices]
                  result.append(tmp_positions*tmp_unit)
              else:
                  raise NotImplementedError
  
      elif element=='residue':
  
          for option in args:
              if option=='n_atoms':
                  raise NotImplementedError
              elif option=='atom_name':
                  raise NotImplementedError
              elif option=='atom_type':
                  raise NotImplementedError
              elif option=='n_residues':
                  raise NotImplementedError
              elif option=='residue_name':
                  raise NotImplementedError
              elif option=='residue_index':
                  raise NotImplementedError
              elif option=='residue_id':
                  raise NotImplementedError
              elif option=='chain_index':
                  raise NotImplementedError
              elif option=='chain_id':
                  raise NotImplementedError
              elif option=='n_frames':
                  raise NotImplementedError
              elif option=='n_chains':
                  raise NotImplementedError
              elif option=='n_molecules':
                  raise NotImplementedError
              elif option=='n_aminoacids':
                  raise NotImplementedError
              elif option=='n_nucleotides':
                  raise NotImplementedError
              elif option=='n_waters':
                  raise NotImplementedError
              elif option=='n_ions':
                  raise NotImplementedError
              elif option=='masses':
                  raise NotImplementedError
              elif option=='charge':
                  raise NotImplementedError
              elif option=='bonded_atoms':
                  raise NotImplementedError
              elif option=='bonds':
                  raise NotImplementedError
              elif option=='graph':
                  raise NotImplementedError
              elif option=='molecules':
                  raise NotImplementedError
              elif option=='molecule_type':
                  raise NotImplementedError
              elif option=='coordinates':
                  raise NotImplementedError
              else:
                  raise NotImplementedError
  
      elif element=='molecule':
          raise NotImplementedError
  
      elif element=='chain':
  
          for option in args:
              if option=='n_atoms':
                  raise NotImplementedError
              elif option=='atom_name':
                  raise NotImplementedError
              elif option=='atom_type':
                  raise NotImplementedError
              elif option=='n_residues':
                  raise NotImplementedError
              elif option=='residue_name':
                  raise NotImplementedError
              elif option=='residue_index':
                  raise NotImplementedError
              elif option=='residue_id':
                  raise NotImplementedError
              elif option=='chain_index':
                  raise NotImplementedError
              elif option=='chain_id':
                  raise NotImplementedError
              elif option=='n_frames':
                  raise NotImplementedError
              elif option=='n_chains':
                  raise NotImplementedError
              elif option=='n_molecules':
                  raise NotImplementedError
              elif option=='n_aminoacids':
                  raise NotImplementedError
              elif option=='n_nucleotides':
                  raise NotImplementedError
              elif option=='n_waters':
                  raise NotImplementedError
              elif option=='n_ions':
                  raise NotImplementedError
              elif option=='masses':
                  raise NotImplementedError
              elif option=='charge':
                  raise NotImplementedError
              elif option=='bonded_atoms':
                  raise NotImplementedError
              elif option=='bonds':
                  raise NotImplementedError
              elif option=='graph':
                  raise NotImplementedError
              elif option=='molecules':
                  raise NotImplementedError
              elif option=='molecule_type':
                  raise NotImplementedError
              elif option=='coordinates':
                  raise NotImplementedError
              else:
                  raise NotImplementedError
  
      elif element=='trajectory':
          raise NotImplementedError
  
      elif element=='system':
  
          for option in args:
              if option=='n_atoms':
                  raise NotImplementedError
              elif option=='charge':
                  raise NotImplementedError
              elif option=='net_charge':
                  raise NotImplementedError
              elif option=='n_degrees_of_freedom':
                  raise NotImplementedError
              else:
                  raise NotImplementedError
  
      else:
          raise NotImplementedError
  
  
      if len(result)==1:
          return result[0]
      else:
          return result
  
  