presto-main/src/main/java/io/prestosql/operator/scalar/StringFunctions.java/StringFunctions/charTrim
class StringFunctions:    @Description("removes whitespace from the beginning and end of a string")
    @ScalarFunction("trim")
    @LiteralParameters("x")
    @SqlType("char(x)")
    public static Slice charTrim(@SqlType("char(x)") Slice slice)
    {
        return trim(slice);
    }