Error:(7, 0) Could not get unknown property 'API_KEY' for ProductFlavor_Decorated{name=main, dimension=null, minSdkVersion=null, targetSdkVersion=null, renderscriptTargetApi=null, renderscriptSupportModeEnabled=null, renderscriptSupportModeBlasEnabled=null, renderscriptNdkModeEnabled=null, versionCode=null, versionName=null, applicationId=null, testApplicationId=null, testInstrumentationRunner=null, testInstrumentationRunnerArguments={}, testHandleProfiling=null, testFunctionalTest=null, signingConfig=null, resConfig=null, mBuildConfigFields={}, mResValues={}, mProguardFiles=[], mConsumerProguardFiles=[], mManifestPlaceholders={}, mWearAppUnbundled=null} of type com.android.build.gradle.internal.dsl.ProductFlavor.