He may be referring to the fact that lambda expressions in Python are limited to a single statement. If you want anything more complex than that, you have to define a function elsewhere and pass it by name.
Two possible issues. As tmhedberg says (more or less), they're second-class citizens: they may contain one expression, and cannot contain any statements (e.g., 'print').<p>A more important issue: in LISP, ML, and other languages with a "proper" lambda, the value of a lambda expression is a lexical closure. Python's lambdas are dynamically scoped, which certainly qualifies as broken.<p>See, e.g., <a href="http://math.andrej.com/2009/04/09/pythons-lambda-is-broken/" rel="nofollow">http://math.andrej.com/2009/04/09/pythons-lambda-is-broken/</a>