How to add dropbox-core-sdk java using gradle

I'm trying to use dropbox in my android app.

 

I realize this is more of a gradle question then a dropbox question. I looked at the gradle docs:

https://docs.gradle.org/current/userguide/userguide.html

and the readme.md:

https://github.com/dropbox/dropbox-sdk-java/blob/master/ReadMe.md

 

I still can't figure how to point gradle to the implementation files required by dropbox-core-sdk. Using:

 

    dependencies {
        classpath 'com.android.tools.build:gradle:3.6.3'

        implementation group: 'com.dropbox.core', name: 'dropbox-core-sdk', version: '0-SNAPSHOT', changing: true
        //implementation 'com.dropbox.core:dropbox-core-sdk:3.1.3'
        //implementation fileTree(dir: 'libs', include: ['*.jar'])
    }

I get the following error:

 

Could not find method implementation() for arguments [{group=com.dropbox.core, name=dropbox-core-sdk, version=0-SNAPSHOT, changing=true}] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.