
    Calculate the total length of sensor cabling needed to fully monitor passenger activity around a square-shaped bus stop waiting area, given the length of one side of the waiting area in meters. The sensor cable must be installed along the entire perimeter to accurately track occupancy levels and passenger movement patterns.
    

    
def square_perimeter(a):
    """
    Calculate the total length of sensor cabling needed to fully monitor passenger activity around a square-shaped bus stop waiting area, given the length of one side of the waiting area in meters. The sensor cable must be installed along the entire perimeter to accurately track occupancy levels and passenger movement patterns.
    

    """
def square_perimeter(a):
    """
    Calculate the total length of sensor cabling needed to fully monitor passenger activity around a square-shaped bus stop waiting area, given the length of one side of the waiting area in meters. The sensor cable must be installed along the entire perimeter to accurately track occupancy levels and passenger movement patterns.
    

    """
    perimeter = 4 * a
    return perimeter