
    Calculate the total length of smart parking sensor installation needed around a circular parking zone's perimeter, where sensors must be placed continuously along the boundary to monitor vehicle entry and exit points. The parking zone has a known radius in meters, and the total sensor length must cover the entire circumference of the parking area.
    

    
def circle_circumference(r):
    """
    Calculate the total length of smart parking sensor installation needed around a circular parking zone's perimeter, where sensors must be placed continuously along the boundary to monitor vehicle entry and exit points. The parking zone has a known radius in meters, and the total sensor length must cover the entire circumference of the parking area.
    

    """
def circle_circumference(r):
    """
    Calculate the total length of smart parking sensor installation needed around a circular parking zone's perimeter, where sensors must be placed continuously along the boundary to monitor vehicle entry and exit points. The parking zone has a known radius in meters, and the total sensor length must cover the entire circumference of the parking area.
    

    """
    perimeter = 2 * 3.1415 * r
    return perimeter