catching wrong exception type

In gluon/gluon/particleGenerator.py, line 42, the function get_table_class() catches the ValueError and that is wrong.

There is only line of code inside the try statement: self.db_models.get(api_name)[table_name].

self.db_models is a dictionary, self.db_models.get(api_name)return None if api_name is not a valid key, otherwise it will return another dictionary.

If api_name is not a valid key, calling self.db_models.get(api_name)[table_name] will throw TypeError: 'NoneType' object has no attribute '__getitem__'

if api_name is valid, but table_name is not a valid key, calling self.db_models.get(api_name)[table_name] will throw KeyError.

here is some definitions of the error types from https://docs.python.org/2/library/exceptions.html

exception ValueError
Raised when a built-in operation or function receives an argument that has the right type but an inappropriate value, and the situation is not described by a more precise exception such as IndexError.

exception KeyError
Raised when a mapping (dictionary) key is not found in the set of existing keys.

exception TypeError
Raised when an operation or function is applied to an object of inappropriate type. The associated value is a string giving details about the type mismatch.