From e722451af13ae9df9dfa63daa8ee754a2788a23f Mon Sep 17 00:00:00 2001
From: Laurens Valk <laurens@pybricks.com>
Date: Tue, 2 Jul 2019 13:08:20 +0200
Subject: [PATCH] api: add Axis.ALL identifier

---
 pybricks/_common.py    | 10 ++++++----
 pybricks/parameters.py |  5 +++++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/pybricks/_common.py b/pybricks/_common.py
index e9cce54..07b4b97 100644
--- a/pybricks/_common.py
+++ b/pybricks/_common.py
@@ -628,17 +628,19 @@ class Accelerometer():
         """
         pass
 
-    def acceleration(self, axis=None):
-        """Measure the acceleration of the device along a given axis in the
+    def acceleration(self, axis=Axis.ALL):
+        """acceleration(axis=Axis.ALL)
+
+        Measure the acceleration of the device along a given axis in the
         :ref:`robot reference frame <robotframe>`.
 
         Arguments:
             axis (Axis): Axis along which the acceleration is
-                         measured. (*Default*: ``None``)
+                         measured. (*Default*: ``axis=Axis.ALL``)
         Returns:
             :ref:`linacceleration`. Returns a :ref:`scalar` of the acceleration
             along the specified axis.
-            If ``axis`` is ``None``, you get a :ref:`vector` with the
+            If you choose ``axis=Axis.ALL``, you get a :ref:`vector` with the
             accelerations along all three axes (x, y, z).
 
         """
diff --git a/pybricks/parameters.py b/pybricks/parameters.py
index 422146e..ec58ea7 100644
--- a/pybricks/parameters.py
+++ b/pybricks/parameters.py
@@ -192,10 +192,15 @@ class Axis():
     .. data:: X
     .. data:: Y
     .. data:: Z
+
+    Some methods let you measure along all axes at once:
+
+    .. data:: ALL
     """
     X = (1, 0, 0)
     Y = (0, 1, 0)
     Z = (0, 0, 1)
+    ALL = None
 
 
 class Align():