There is a lot of room for improvements (use of lexical variables instead of package variables, elimination of constant 2nd arg for bless, elimination of indirect method invocation), but the problem is that $arg has a newline.

Change
$arg=<stdin>;
to
chomp($arg=<stdin>);

Ref: chomp, IO Operators

Update: Oh and change
print $arg;
to
return $arg;

In reply to Re: Accessing values of a Hash object by ikegami
in thread Accessing values of a Hash object by dReKurCe

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