import math


def get_exact_angle(pt1, pt2):
    """
    Given two cardinal points, returns the corresponding angle
    in *radians*.

    Args:
       * **pt1** (tuple):  Point 1
       * **pt2** (tuple):  Point 2

    Returns:
       float  Angle (in radians)

    Example::

        import picwriter.toolkit as tk
        print(tk.get_angle((0, 0), (100, 100)))

    The above prints 0.785398163

    """
    dx, dy = pt2[0]-pt1[0], pt2[1]-pt1[1]
    return math.atan2(dy,dx)