How group by and sum values in DataTable?

How group by and sum values in DataTable??

I have a DataTable that looks like this:

Id Value
1 4.0
1 5.0
3 1.0
2 2.0
3 3.0

I want to end up with (probably a new DataTable) that contains the sum of
values grouped by Id like this:

Id SumOfValue
1 9.0
2 2.0
3 4.0

pls help me.......

Thanks!

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