This function will open file named filename, read and parse its content and return a string of resulting Python code.
If dir is specified, then the ultimate filename to be parsed
is constructed by concatenating dir and filename, and
the argument to
include directive can be specified as a
relative path. (Note that this is a simple concatenation, no path
separator will be inserted if dir does not end with one).
This function will parse contents of string and return a string of resulting Python code.