what is the syntax to update alias with groovy script

Summary:

Is there a syntax to update alias using a groovy script? We would like to update the alias of a period member based on the start period of the actual scenario.

Content (please ensure you mask any confidential information):

// Define variables based on current system values
Member theActMbr = null
Member theCYTM1 = null

// Set variables equal to current system values
try {
theActMbr = operation.application.getDimension('Scenario').getMember("Actual")
theCYTM1 = operation.application.getDimension("Period").getMember("CYM1")
}
catch (Exception e) {
// Silent fail
}
String thesetalias = 'CYTTM-Jan'

if (theActMbr == "Jan") {
theCYTM1.setAlias("Default", thesetalias) // "Default" is the alias table name
}

Script compilation error. - for the if statement section