code: boolean isAssignableKey(Method getter) {
          synchronized (autoGeneratedKeyGetterCache) {
              if ( !autoGeneratedKeyGetterCache.containsKey(getter) ) {
                  autoGeneratedKeyGetterCache.put(
                          getter,
                          getter.isAnnotationPresent(DynamoDBAutoGeneratedKey.class)
                                  && (getter.isAnnotationPresent(DynamoDBHashKey.class) || getter
                                          .isAnnotationPresent(DynamoDBRangeKey.class)));
              }
          }
  
          return autoGeneratedKeyGetterCache.get(getter);
      }
docs: Returns whether the method given is an assignable key getter.