adding docstrings to robot.head_speed

Author: andySigler

docs/source/api.rst

@@ -13,7 +13,7 @@ Robot
 All protocols are set up, simulated and executed using a Robot class.
 
 .. autoclass:: Robot
-   :members: connect, home, reset, run, simulate, commands, move_to, containers, actions, disconnect, pause, resume, stop, diagnostics, get_warnings, add_instrument, get_mosfet, get_motor
+   :members: connect, home, reset, run, simulate, commands, move_to, containers, actions, disconnect, head_speed, pause, resume, stop, diagnostics, get_warnings, add_instrument, get_mosfet, get_motor
 
 Pipette
 -----------------

opentrons/robot/robot.py

@@ -31,6 +31,7 @@ class Robot(object, metaclass=Singleton):
         * :meth:`run` the protocol on a robot
         * :meth:`home` axis, move head (:meth:`move_to`)
         * :meth:`pause` and :func:`resume` the protocol run
+        * set the :meth:`head_speed` of the robot
 
     Each Opentrons protocol is a Python script. When evaluated the script
     creates an execution plan which is stored as a list of commands in
@@ -497,6 +498,26 @@ def move_plunger(self, *args, **kwargs):
         self._driver.move_plunger(*args, **kwargs)
 
     def head_speed(self, rate):
+        """
+        Set the XY axis speeds of the robot, set in millimeters per minute
+
+        Parameters
+        ----------
+        rate : int
+            An integer setting the mm/minute rate of the X and Y axis.
+            Speeds too fast (around 6000 and higher) will cause the robot
+            to skip step, be careful when using this method
+
+        Examples
+        --------
+        >>> from opentrons import robot
+        >>> robot.connect('Virtual Smoothie')
+        True
+        >>> robot.home()
+        True
+        >>> robot.head_speed(4500)
+        >>> robot.move_head(x=200, y=200)
+        """
         self._driver.set_head_speed(rate)
 
     @traceable('move-to')