Unable to determine Swift version for the following pods

OC項目使用pod集成一個Swift庫時報錯：

[!] Unable to determine Swift version for the following pods:

• Pod33 does not specify a Swift version and none of the targets (TestBundle) integrating it have the SWIFT_VERSION attribute set. Please contact the author or set the SWIFT_VERSION attribute in at least one of the targets that integrate this pod.

這個解釋是說需要在OC項目中設置Swift版本。
Build Settings -》 點擊+號，添加“Add User-Defined setting” -> 將新添加的設置命名爲“ SWIFT_VERSION” -》設置值爲5.0