Nested Logit


I was wondering if anyone could help me with estimating a nested logit with a specific nesting structure.
The choice set represents possible occupations as follows: 1. professional/technical, 2. managers/ admin, 3. sales, 4. clerical / unskilled, 5. craftsmen, 6. operatives, 7. transport, 8. others.
The task is asking me to estimate a nested logit with the following nesting structures:

  1. white collar occupations (indexed by WC): including 1 2 3 above
  2. blue collar occupations (indexed by BC): 4 5 6 7
  3. other occupations (indexed by other): other

I have to specify the parameters s.t there are only nest level coefficients and print them.

While I have attempted for a couple of days, the code is still not functioning properly.

Thank you for any help.

It would probably help if you post the code that you tried.