Generated Bash completion script does not complete any options

[schoettl]

Option completion does not work at all in Bash.

$ backend --help
usage: backend [options]

options:
  -H, --no-hardware
    Use hardware mockup instead of real hardware.
$ docopt-completion backend --manual-bash
Completion file written to ./backend.sh

Generated completion function is:

_backend()
{
    local cur
    cur="${COMP_WORDS[COMP_CWORD]}"

    if [ $COMP_CWORD -ge 1 ]; then
        COMPREPLY=( $( compgen -W ' ' -- $cur) )
    fi
}

The options are not mentioned in this script and (after sourcing it) option completion does not work.