<action_sequence_index>: the number returned by
[:SOURce]:ACTion[1|2]:DEFine[:NEW]?
<action>: Basic command enum
<value>: Value(s) to be set
This command defines the next step of an action sequence. Each step consists of an
action identifier enum and 0 or more double values.
If the action table is full, an error is returned.
If the same <action> is appended more than once, only its last value is used.
If more than on <action> in the set {Sweep Run, Sweep Hold, Sweep Restart} is
issued, all but the last are discarded.
The default value for the optional fractional parts is 0.0.