Update values in XML file [closed]

[Casper10]

I am having XML file with the following format:\[code\]<Principal ID="122" ><Status Fees="${Fees}"/></Principal><Principal ID="123" ><Status Fees="${Fees}"/></Principal><Principal ID="124" ><Status Fees="${Fees}"/></Principal><Principal ID="125" ><Status Fees="${Fees}"/></Principal>\[/code\]I need to update \[code\]${Fees}\[/code\] variable with Fees1, Fees2, Fees3 and so on. There are more than 365 records.Can someone help me how to do this through Perl or Python?