Get prefix.
get_prefix(object, ...)# S4 method for compartment_bioavailability
get_prefix(object, ...)
# S4 method for compartment_lag_time
get_prefix(object, ...)
# S4 method for compartment_infusion_duration
get_prefix(object, ...)
# S4 method for compartment_infusion_rate
get_prefix(object, ...)
# S4 method for compartment_initial_condition
get_prefix(object, ...)
the prefix of this object
generic object
e.g. dest='mrgsolve'