Issue in summing two custom lasers about fbpic HOT 3 CLOSED

class LaserProfile( object ):
    def __init__( self, propagation_direction, gpu_capable=False ):
        assert propagation_direction in [-1, 1]
        self.propag_direction = float(propagation_direction)
        self.gpu_capable = gpu_capable

    def E_field( self, x, y, z, t ):
        return( np.zeros_like(x), np.zeros_like(x) )

from fbpic.lpa_utils.laser.laser_profiles import LaserProfile