what am I missing (syntax error)

[orangeDinosaur]

Here's  a section of code:

for x in occupants:
			if x not in uniqueUsers and not in staff: uniqueUsers.append(x)
			elif x in staff and not in uniqueStaff:	uniqueStaff.append(x)

When I try to import the module with the function definition that
contains this code, I get a syntax error pointing to the 'in' after the
'and not in staff'.  I can't figure out why this is bad syntax.  Both
'uniqueUsers' and 'staff' are lists.  

thanks for your help!