def point_in_circle(pt, center, radius):
    '''
    Returns true if a given point is located inside (or on the border) of a circle.
    
    >>> point_in_circle((0, 0), (0, 0), 1)
    True
    >>> point_in_circle((1, 0), (0, 0), 1)
    True
    >>> point_in_circle((1, 1), (0, 0), 1)
    False
    '''
    d = np.linalg.norm(np.asarray(pt) - np.asarray(center))
    return d <= radius
Returns true if a given point is located inside (or on the border) of a circle.
    
    >>> point_in_circle((0, 0), (0, 0), 1)
    True
    >>> point_in_circle((1, 0), (0, 0), 1)
    True
    >>> point_in_circle((1, 1), (0, 0), 1)
    False