def file$\_$split$($f$\_$in$,$ f$\_$digits, f$\_$no$\_$digits$)$:

$"""$

$-------------------------------------------------------$

Copies the contents of f$\_$in to f$\_$digits and f$\_$no$\_$digits depending

on the contents of f$\_$in:

Lines containing digits are copied to f$\_$digits.

Lines without digits are copied to f$\_$no$\_$digits.

Empty lines are ignored.

Use: file$\_$split$($f$\_$in$,$ f$\_$digits, f$\_$no$\_$digits$)$

$-------------------------------------------------------$

Parameters:

f$\_$in $-$ source file $($file handle $-$ already open for reading$)$

f$\_$digits $-$ file to contain lines with digits from f$\_$in $($file handle

$-$ already open for writing$)$

f$\_$no$\_$digits $-$ file to contain non$-$empty lines without digits from f$\_$n

$($file handle $-$ already open for writing$)$

Returns$$:

None

$-------------------------------------------------------$

$"""$