If ParameterValueType.Range, this defines the step date period
used in the Parameter UI control slider. Note that if you specify a new value for the parameter,
using the changeValueAsync() method, that does not align on the dateStepPeriod interval, the
value will be set to the closest, earlier date.
If ParameterValueType.Range, the value will be the lower
bound of allowable values for the parameter.
Optional stepSize
stepSize:undefined | number
returns
If ParameterValueType.Range, the value will
define the step size used in the parameter UI control slider.
Note that if you specify a new value for the parameter, using the changeValueAsync() method,
that does not align on the stepSize interval, the value will be set to the closest, lower interval.
For example, if the stepSize was 5 and the steps were 1, 5, 10, if the new value specified
was 8, the value 5 would be used instead.
Represents the allowable set of values which a parameter can be set to.