What is the purpose of banjo lesson by Henry tanner?

There isn't a specific piece of art called "Banjo Lesson" by Henry Tanner. Henry Ossawa Tanner was a prominent African American artist known for his religious themes and realistic portrayals of African American life.

It's possible you're thinking of a different piece by Tanner or perhaps another artist altogether. Could you please provide more information or context about the artwork you're interested in?

For example:

* What is the subject matter of the piece? (e.g., a musician, a specific scene, a religious theme)

* Do you have any details about the artwork, like its date, size, or location?

* Is there a specific image or a description of the artwork available?

With more information, I can help you identify the artwork and understand its purpose.