Python helper functions

util.py

def find(func, i):
    """
    Finds the first match in an iterable
    Works like `filter` but returns a single item
    """
    try:
        return next(filter(func, i))
    except StopIterator:
        raise ValueError("No matching item found")


def flatten(i, key=None):
    """
    Convert an iterable `i` of dictionaries
    with key `key` of lists to a list
    i.e. [{'a': [1,2]}, {'a': [3,4]}] -> [1,2,3,4]
    """
    i = iter(i)
    first = next(i)
    if key is None:
        key = next(iter(first.keys()))
    items = first[key]
    for item in i:
        items.extend(item[key])
    return items