resolve go-python#169 (comment)

Author: glaukiol1

os/os.module.go

@@ -9,7 +9,6 @@ package os
 import (
 	"os"
 	"os/exec"
-	"reflect"
 	"strings"
 
 	"github.com/go-python/gpython/py"
@@ -167,18 +166,16 @@ func putenv(self py.Object, args py.Tuple) (py.Object, error) {
 // Unset (delete) the environment variable named key.
 func unsetenv(self py.Object, args py.Tuple) (py.Object, error) {
 	if len(args) == 1 && objectIsString(args[0]) {
-		if reflect.TypeOf(args[0]).String() == "py.String" {
-			_k, err := py.ReprAsString(args[0])
-			if err != nil {
-				return nil, py.ExceptionNewf(py.TypeError, "Unable to parse string") // this will never execute
-			}
-			key := strings.ReplaceAll(_k, "'", "") // required
-			err = os.Unsetenv(key)
-			if err != nil {
-				return nil, py.ExceptionNewf(py.OSError, "Unable to unset enviroment variable")
-			}
-			return py.None, nil
+		_k, err := py.ReprAsString(args[0])
+		if err != nil {
+			return nil, py.ExceptionNewf(py.TypeError, "Unable to parse string") // this will never execute
 		}
+		key := strings.ReplaceAll(_k, "'", "") // required
+		err = os.Unsetenv(key)
+		if err != nil {
+			return nil, py.ExceptionNewf(py.OSError, "Unable to unset enviroment variable")
+		}
+		return py.None, nil
 	}
 	if len(args) == 0 {
 		return nil, py.ExceptionNewf(py.TypeError, "missing one required argument: 'key:str'")