+ fix dangling pointers when fetching Python error text
+ initialize members in overloaded constructors of Exception class
+ implement assignment operator in sub-class
+ move to PyCXX API to simplify handling with reference counting and reading values from the dict
- (error) va_list '<var>' was opened but not closed by va_end()
- (style) Same expression on both sides of '||'
- (style) Same expression on both sides of '!='
