Merge pull request #3651 from JuliaReach/schillic/hpolytope

Fix HPolytope constructor with old Symbolics version

src/Initialization/init_Symbolics.jl

@@ -7,7 +7,12 @@ _vec(vars::Vector{Symbolics.Arr{Num,1}}) = reduce(vcat, vars)
 _vec(vars::Vector{Vector{Num}}) = reduce(vcat, vars)
 _vec(vars::Vector{Real}) = reduce(vcat, vars)
 
-_get_variables(expr::Num) = convert(Vector{Num}, Symbolics.get_variables(expr; sort=true))
+# `sort` argument was introduced in Symbolics v6.1
+@static if VERSION < v"1.10"
+    _get_variables(expr::Num) = convert(Vector{Num}, Symbolics.get_variables(expr))
+else
+    _get_variables(expr::Num) = convert(Vector{Num}, Symbolics.get_variables(expr; sort=true))
+end
 function _get_variables(expr::Vector{<:Num})
     return unique(reduce(vcat, _get_variables(ex) for ex in expr))
 end