The rest of the name tells you the particular value to
which it refers.  Most often, it consists of a single
identifier, that is, a string beginning with a letter
or underscore, and containing letters, underscores, and
digits.

##</code><code>##

my %bad = (
    '12598' => {},   # data about bad sequence
    '19203' => {},   # data about other bad sequence
)

##</code><code>##

$12598{'foo'} = 'bar';   # wrong and illegal

##</code><code>##

$bad{'12598'}{'foo'} = 'bar';