require Some::Module in a single function

.pl

sub cfsqrt {
    my ($self, $n, $m) = @_;
    $m ||= $n;
    my @terms;
    my $ok = eval {                                                                                                                                                          
        require Math::NumSeq::SqrtContinued;
        1;
    };
    die 'ERROR: Math::NumSeq::SqrtContinued not installed'
        unless $ok;

    my $seq = Math::NumSeq::SqrtContinued->new(sqrt => $n);
    for my $i (1 .. $m) { 
        my ($j, $value) = $seq->next;
        push @terms, $value;
    } 
    return \@terms;
}