import re


def natural_sort(key):
    """Key to sort a list of strings containing numbers in natural order.

    This function is used to customize the sorting of lists of strings. For 
    example, it ensures that 'label_10' follows 'label_9' after sorting.
    
    Parameters
    ----------
    key : str
        String in the list to be sorted.
    
    Returns
    -------
    list
        List of string components splitting embedded numbers as integers.
    """
    return [int(t) if t.isdigit() else t for t in re.split(r'(\d+)', key)]