code: public Key<?> getKey(MethodLiteral<?, ?> method) {
      if (isMemberInject(method)) {
        return getKey(method.getParameterTypes().get(0).getType(), method.getBindingAnnotation());
      }
      return getKey(method.getReturnType().getType(), method.getBindingAnnotation());
    }
docs: Retrieves a key based on the passed {@link Ginjector} method. If the
  passed method is used for member injection, returns a key for the
  parameter, otherwise for the method return type. Always uses the method's
  binding annotation if present.
  
  @param method method for which to retrieve the key
  @return key based on passed method