dropbear using multiple host keys at one time (RSA, ECDSA)

I found out that in the dropbear -h it says ( I am really confused about what does the repeatable mean)

-r keyfile Specify hostkeys (repeatable) defaults:

- dss /etc/dropbear/dropbear_dss_host_key

- rsa /etc/dropbear/dropbear_rsa_host_key

- ecdsa /etc/dropbear/dropbear_ecdsa_host_key

- ed25519 /etc/dropbear/dropbear_ed25519_host_key

I am trying to let my dropbear server use both rsa and ecdsa, is that gonna work ? if so what is the right input

I tried dropbear -r -rsa dropbear_rsa_host_key -ecdsa dropbear_ecdsa_host_key

it only enables the rsa host key but not ecdsa host key

I believe if you put both keys in openssh sshd_config the openssh server will try both of them, I wonder how this is being done in dropbear