code: def get_modifications(self):
          
          for modtype, modclass in modtype_to_modclass.items():
              # TODO: we could possibly try to also extract generic
              # modifications here
              if modtype == 'modification':
                  continue
              stmts = self._get_generic_modification(modclass)
              self.statements += stmts
docs: Extract INDRA Modification Statements from the BioPAX model.
  
          To extract Modifications, this method reuses the structure of
          BioPAX Pattern's
          org.biopax.paxtools.pattern.PatternBox.constrolsStateChange pattern
          with additional constraints to specify the type of state change
          occurring (phosphorylation, deubiquitination, etc.).