has arg => qw(is rw isa ArrayRef), default => sub { [] }; # untidy

##</code><code>##

has
arg => qw(is rw isa ArrayRef),
default => sub { [] }; # nooooooo

##</code><code>##

has arg => qw(is rw isa ArrayRef),
   default => sub { [] }; 

# much better, although I don't mind the indentation
# the crucial thing is the "has arg" part