Update unit_check.jl

Author: ChrisRackauckas

src/systems/unit_check.jl

@@ -43,6 +43,18 @@ function __get_unit_type(vs′...)
     return nothing
 end
 
+
+function screen_unit(result::DQ.AbstractQuantity)
+    d = DQ.dimension(result)
+    if d isa DQ.Dimensions
+        return result
+    elseif d isa DQ.SymbolicDimensions
+        return DQ.uexpand(oneunit(result))
+    else
+        throw(ValidationError("$result doesn't have a recognized unit"))
+    end
+end
+
 function screen_unit(result)
     throw(ValidationError("$result doesn't have any unit."))
 end