[[boost.python]] tries hard to provide best possible run-time errors.
But often enough they need futher explanation.
Some of them are mentioned below:

=== TypeError: bad argument type for built-in operation ===
Usualy means BPL couldn't find c++ method/function with appropriate signature.
Very often that is wrong number of arguments, wrong argument(s) type and so on.

=== TypeError: No to_python converter found for C++ type: <type> ===
=== TypeError: No to_python (by-value) converter found for C++ type: <type> ===
BPL was unable to get C++ value from Python object.

For example, when calling {{{ extract<int>(<object>.attr("__len__")()) }}} to get object length
you omitted "'''()'''".

=== RuntimeError: This class cannot be instantiated from Python ===
Attempt to instantiate a class with ''no_init'' descriptor.
It may be private constructor or abstract class.

=== RuntimeError: unidentifiable C++ Exception ===
Boost.Python provides a default exception handler that translates selected standard exceptions, then gives up
with that message.

To install your own exception translator '''don't''' see [[http://www.boost.org/libs/python/doc/tutorial/doc/exception_translation.html|tutorial]]. :) ('''&''' missed in register_exception_translator call)
<<BR>>
Use that: {{{
struct PodBayDoorException;
void translator(const PodBayDoorException& x) {
  PyErr_SetString(PyExc_UserWarning, "I'm sorry Dave...");
}
BOOST_PYTHON_MODULE(kubrick) {
  register_exception_translator<
  PodBayDoorException>(&translator);
  ...
}
}}}