Python scripting in 2.1.2 is currently in beta and unfortunately there is a bug that blocks the response. We have already addressed this issue and the fix will be available in the next release. However, if you really need to get this going before the next release comes out then feel free to make this small modification and it should work for you.
Edit file vendor/dreamfactory/df-core/src/Scripting/Engines/Python.php and drop the following code before the closing curly braces ( } ) near the end of this file.
/** @inheritdoc */
protected function checkOutputStringForData($output)
{
return ((strlen($output) > 10) && (false !== strpos($output, 'request')));
}