arbiter.get_sharing_mode() is ambiguous

[bmayton]

The name of the function "get_sharing_mode" is not conducive to readable code. Didn't this used to be called "is_instructor" or something similar?

The following:

if self.__arbiter.get_is_instructor():
   blah

is a lot more clear than:

if self.__arbiter.get_sharing_mode():
   blah

The second (which is the current implementation) doesn't allow the reader to infer that it returns a boolean, and what the values of True or False imply. The first makes both of these clear.

[plunkett]

I agree. Made changes per Brian's advice in the description of this ticket.

Changeset 107