Somewhere it says "the file handle for print must be a real filehandle not a reference to one".  Apparently, the object itself (that is $self->{'fh'} or more precisely \{$self->{'fh'}}) is being passed to print instead of being evaluated first like the arguments in a list being passed to a function would be.  This has to do with the whole indirect-object-notation semantics (that is a first argument with no comma after it).

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