Powerful Command line parsers

[PyPK]

Is there a Command line parser in python that can:
1. resolve conflicts
2. specify something like requires
3. and smart

for ex:
python test.py --a --b --c --d

Case 1:
If 'a' is an option 'b' or 'c' cannot be specified.

Case 2:
atleast one option should be specified

Case 3:
IF 'a' and 'c' are given then 'd' has to be given

or  many such cases.

I was wondering as this is a very common problem there if there is a
module that could do these things .
'optparse' is not this smart I guess.