def find_zeros(matrix):
    """Returns a dict  with list of rows and columns that contain zeros
    within the matrix

    >>> zero_coordinates = find_zeros([['0', 'w', 'e'], ['a', 's', 'd'], ['z', 'x', '0']])
    >>> sorted(zero_coordinates.items())
    [('columns', [0, 2]), ('rows', [0, 2])]
    """
    rows = []
    columns = []
    coordinates = {'rows': rows, 'columns': columns}
    for list_number, list in enumerate(matrix):
        for element_number, element in enumerate(list):
            if element == '0':
                coordinates['rows'].append(list_number)
                coordinates['columns'].append(element_number)
    return coordinates