MIME_TYPE outptup is not compatible with variable type "Mime content type"


I need to determine the mime content type of file stored locally.

I create a variable calle mimeType of type Mime content type

I use the function MIME_TYPE that according to the manual should provide the MIME type but the result is incompatible with the Mime content type, seems to be a text.

How can I convert a text to mime content type ?

Thank you