You should read the documentations of
Inline itself:
In case you've forgotten, the DATA pseudo file is comprised of all the text after the __END__ or __DATA__ section of your program. If you're working outside the main package, you'd best use the __DATA__ marker or else Inline will not find your code.
perldata might also be of interest:
For compatibility with older scripts written before __DATA__ was introduced, __END__ behaves like __DATA__ in the top level script (but not in files loaded with "require" or "do") and leaves the remaining contents of the file accessible via "main::DATA".
use says:
use Module LIST... is exactly equivalent to
BEGIN { require Module; Module->import( LIST ); }
except that Module must be a bareword.
