'Set the orientation of the turtle to to_angle.
Aliases:  setheading | seth
Argument:
to_angle -- a number (integer or float)
Set the orientation of the turtle to to_angle.
Here are some common directions in degrees:
standard - mode:          logo-mode:
0 - east                0 - north
90 - north              90 - east
180 - west              180 - south
270 - south             270 - west
Example (for a Turtle instance named turtle):
>>> turtle.setheading(90)
>>> turtle.heading()
90'

def setheading(self, to_angle):

    angle = ((to_angle - self.heading()) * self._angleOrient)
    full = self._fullcircle
    angle = (((angle + (full / 2.0)) % full) - (full / 2.0))
    self._rotate(angle)
