docs: def define_all_protein_rings(self):
          """Make MDAnalysis atom selections for rings in protein residues that will be plotted in the final figure - since they are the only ones that
          should be analysed.
          Saves the rings in self.protein_rings dictionary.
          """
          self.protein_rings = {}
          i=0
          for residue in self.topology_data.dict_of_plotted_res:
              for ring in self.rings:
                  if ring[0]==residue[0]:
                      atom_names =""
                      for atom in self.rings[ring]:
                          atom_names = atom_names+" "+atom
                      self.protein_rings[i]= self.topology_data.universe.select_atoms("resname "+residue[0]+" and resid "+residue[1]+" and segid "+ residue[2]+" and name "+atom_names)
                      i+=1