pass a block of parameters to doveadm

[dovecot-user]

Hello everyone.
Please tell me how to override the configuration file options when using 
the doveadm utility with the -o switch in case I need to pass a block of 
parameters, for example, like this:
passdb {
   args = scheme=PLAIN username_format=%u /path/to/file
   driver = passwd-file
}
Thanks.