Symbols in Symbol Utilities

General Usage
1

I’m trying to use various CAS packages. I tried to follow the instructions for. Symbolic Utils

Using SymbolicUtils

@syms x

diff(x^2+x,x)

and I get

ERROR: MethodError: no method matching diff(::Term{Number}, ::Sym{Number})
Stacktrace:
 [1] top-level scope at REPL[70]:1

when I run

using SymbolicUtils
using SymEngine

x=symbols(:x)
SymbolicUtils.diff(x^2+x,x)

I get the correct result, 2x+1.