Python lambda is somewhat limited, compared to lambda in some other languages. Guido isn't overly fond of lambda or other functional building blocks (and even planned to remove it from Python, before there was a sufficient outpouring of support for keeping it). http://www.artima.com/weblogs/viewpost.jsp?thread=98196
As I understand it, the primary limitation is that Python lambda only works with a single expression (I think it also has some weirdness regarding scope when calling functions?). I haven't poked seriously at Python since around about the time they were talking about removing it, so I probably have no idea what I'm talking about.
The idea is that generators and list comprehensions do the things most people do with lambdas in a more Pythonic way.
Python lambdas are explicitly artificially limited to a single expression. Python has statements which are not expressions, mostly control statements and looping constructs.
The syntax isn't the greatest, but you can get pretty far with Python's ternary expression. Generators in my experience remove the need for most loops. Where lambdas feel really subpar for me is the lack of 'let' and error-handling.
While it IS a conscious decision to force lambdas to be a single expression, extending it to be able to be multiline would screw up with indentation being irrelevant inside of a function call too.
