def __init__(self, radius, angle):
        """ define a sector range for attack or view

        Parameters
        ----------
        radius : float
        angle :  float
            angle should be less than 180
        """
        self.radius = radius
        self.angle  = angle
        if self.angle >= 180:
            raise Exception("the angle of a sector should be smaller than 180 degree")
 define a sector range for attack or view

        Parameters
        ----------
        radius : float
        angle :  float
            angle should be less than 180
        
python/magent/gridworld.py