def in_circle(x, y, x0, y0, r):
    """
    Check if a point (x, y) is in the circle centered at (x0, y0) with
    redius r
    """

    dr = (x-x0)**2 + (y-y0)**2 - r**2
    if dr <= 0:
        check = True
    else:
        check = False

    return check