code: def resolve_realms(self, attributes):
          
          realms = []
  
          for realm, realm_attributes in attributes['realms'].items():
              realm_cls = maybe_resolve(realm)
              account_store_cls = maybe_resolve(realm_attributes['account_store'])
  
              verifiers = {}
  
              authc_verifiers = realm_attributes.get('authc_verifiers')
              if authc_verifiers:
                  if isinstance(authc_verifiers, list):
                      authc_verifiers_cls = tuple(maybe_resolve(verifier)(self.settings) for
                                                  verifier in authc_verifiers)
                  else:
                      authc_verifiers_cls = tuple([maybe_resolve(authc_verifiers)(self.settings)])
                  verifiers['authc_verifiers'] = authc_verifiers_cls
  
              authz_verifier = realm_attributes.get('authz_verifier')
              if authz_verifier:
                  permission_verifier_cls = maybe_resolve(authz_verifier)
                  if permission_verifier_cls:
                      verifiers['permission_verifier'] = maybe_resolve(permission_verifier_cls)()
  
              realms.append([realm_cls, account_store_cls, verifiers])
  
          return realms
docs: The format of realm settings is:
              {'name_of_realm':
                  {'cls': 'location to realm class',
                   'account_store': 'location to realm account_store class'}}
  
              - 'name of realm' is a label used for internal tracking
              - 'cls' and 'account_store' are static key names and are not to be changed
              - the location of classes should follow dotted notation: pkg.module.class