Well in a dynamically typed language there is also the possibility than something you expect to be an integer is in fact a string. Null or Nil or None is not di

Well in a dynamically typed language there is also the possibility than something you expect to be an integer is in fact a string. Null or Nil or None is not different in this respect than any other type. But of course you can make bugs involving nulls. The OP shows an example in a dynamic language where null is returned instead of the regular value if a lookup key is not found. Obviously this is ambiguous when the found value can also be null. But the problem is not the null per se, the problem is using a sentinel value to indicate a special condition when the same value is also a legitimate regular value. This is just bad API design.