Difference between date culumns with an IF like statement

Hey guys,

I am using PowerBi in my company to create some dashboards, and I need to incorporate a calculated column in my data set that calculates the following :

1/ The difference in Days between column [StartDate] and [EndDate]

2/ However if the [EndDate] row is empty, it should use (Today) as a date

I appreciate the help.

Regards,

Khal