from typing import List
from typing import Any


def flatten_list(x: List[Any]) -> List[Any]:
    """
    Converts a list of lists into a flat list.
    
    Args:
        x: list of lists 

    Returns:
        flat list
        
    As per
    http://stackoverflow.com/questions/952914/making-a-flat-list-out-of-list-of-lists-in-python

    """  # noqa
    return [item for sublist in x for item in sublist]