
    Given a complex urban parking system with multiple zones and sub-zones represented as nested lists of parking space IDs, create a function that consolidates all individual parking space identifiers into a single unified set for real-time occupancy tracking. The function should process hierarchical parking zone data and output a flat set of unique parking space IDs, enabling efficient system-wide availability monitoring and space allocation.
    

    
def extract_singly(test_list):
    """
    Given a complex urban parking system with multiple zones and sub-zones represented as nested lists of parking space IDs, create a function that consolidates all individual parking space identifiers into a single unified set for real-time occupancy tracking. The function should process hierarchical parking zone data and output a flat set of unique parking space IDs, enabling efficient system-wide availability monitoring and space allocation.
    

    """
def extract_singly(test_list):
    """
    Given a complex urban parking system with multiple zones and sub-zones represented as nested lists of parking space IDs, create a function that consolidates all individual parking space identifiers into a single unified set for real-time occupancy tracking. The function should process hierarchical parking zone data and output a flat set of unique parking space IDs, enabling efficient system-wide availability monitoring and space allocation.
    

    """
    res = []
    temp = set()
    for inner in test_list:
        for ele in inner:
            if not ele in temp:
                temp.add(ele)
                res.append(ele)
    return res