Argument 1: cannot convert from 'System.Collections.Generic.IEnumerable<uint?>' to 'System.Collections.Generic.IEnumerable<uint>'

Argument 1: cannot convert from 'ulong?' to 'long'

Cannot implicitly convert type 'long' to 'uint'. An explicit conversion exists (are you missing a cast?)

Cannot implicitly convert type 'ulong' to 'long?'. An explicit conversion exists (are you missing a cast?)

An expression of type 'long?' cannot be handled by a pattern of type 'ulong'.

The call is ambiguous between the following methods or properties: 'Enumerable.Sum<TSource>(IEnumerable<TSource>, Func<TSource, decimal>)' and 'Enumerable.Sum<TSource>(IEnumerable<TSource>, Func<TSource, float>)'

Argument 1: cannot convert from 'System.Collections.Generic.IEnumerable<uint?>' to 'System.Collections.Generic.IEnumerable<uint>'

Argument 1: cannot convert from 'ulong?' to 'long'

Cannot implicitly convert type 'long' to 'uint'. An explicit conversion exists (are you missing a cast?)