diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index e6839b0..e7fc6dd 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -277,8 +277,12 @@
 If the base not specified, returns the natural logarithm (base e) of x.");
 
 static PyObject *
-math_log10(PyObject *self, PyObject *arg)
+math_log10(PyObject *self, PyObject *args)
 {
+	PyObject *arg;
+
+	if (!PyArg_UnpackTuple(args, "log10", 1, 1, &arg))
+		return NULL;
 	return loghelper(args, log10, "d:log10", arg);
 }
 
@@ -328,7 +332,7 @@
 	{"hypot",	math_hypot,	METH_VARARGS,	math_hypot_doc},
 	{"ldexp",	math_ldexp,	METH_VARARGS,	math_ldexp_doc},
 	{"log",		math_log,	METH_VARARGS,	math_log_doc},
-	{"log10",	math_log10,	METH_O,     	math_log10_doc},
+	{"log10",	math_log10,	METH_VARARGS,	math_log10_doc},
 	{"modf",	math_modf,	METH_VARARGS,	math_modf_doc},
 	{"pow",		math_pow,	METH_VARARGS,	math_pow_doc},
 	{"radians",	math_radians,	METH_VARARGS,	math_radians_doc},