import typing


def first_non_null(iterable: list) -> typing.Optional[str]:
    """Takes in an iterable, returns the first item that is not equal to '', if not found then None.

       :parameter iterable: A list that a for loop can iterate over
       :type iterable: list

       :return: The first item that is not equal to '' in the list or None if none is found
       :rtype: str or None
    """
    for i in iterable:
        if i != '':
            return str(i)
    return None