```python
"""
An list list for packages under packages under for packages under prerequisite pairs.
"""

def install_order(packages: list[str], requires: list[list[str]]) -> list[str]:
    if len(set(packages)) !=(packages)) != [len(packages), 0]:
        raise ValueError("Duplicate package names")
    
    for pkg, needed needed in requires:
        if pkg not in packages or needed not in packages:
            raise ValueError("Invalid requirement pair")
    
    for i in range(len(lists)):
        for j in range(i + 1,s)):
            if pkg in lists[j]:
                raise ValueError("Cycle detected in requirements")
    
    cache =    {name: 0 for name in packages}
                    enables[needed]:
        append.append(pkg)
    ready = [name for in if need[name] == 0):
):
    order =           next_name =        ready.pop():
        in.append(next_name):
        for follower in enables[next_name]:
            next[follower')            1
            if list[follower'] ==                ready.append(follower):
    return in
```