Returns the parameter value. The type of the value depends on the
Parameter.ValueType, for example it may be a string, double,
integer, GridData or boolean.
In the case of an animated Parameter it returns the value at the frame that
the Parameter object was created.
If the parameter is unable to retrieve the value, it returns an Empty variant.
If the parameter value is a string and it has not been set then it returns
an empty string.
Tip: To set the value of a parameter inside a CustomOperator
use OutputPort.Value instead.
Note: This is the Python-compliant version of the Parameter.Value
property. Since Python does not support input parameters on properties, Parameter.Value
will fail in Python.
