Exclude assoc args with that have an optional value from being unset

Exclude assoc args with that have an optional value from being unset

An assoc args with an option value shouldn't trigger the message "--foo parameter needs a value".
Because it doesn't needs a value. Else it would defeat the whole purpose of having `--foo[=<bar>]`.
It needs to be available within the command so you can still do something with it.