def multiSearch(lst, val):
    """
    Return a list of (the positions of) all occurrences
    of val in lst.
    
    >>> testlist = [5, 2, 9, 8, 9, 2, 6, 0, 9, 1]
    >>> multiSearch(testlist, 9)
    [2, 4, 8]
    >>> multiSearch(testlist, 4)
    []
    >>> multiSearch(testlist, 0)
    [7]
    """
    found = []
    for pos in range(len(lst)):
        if lst[pos]==val:
            found.append(pos)
    
    return found



# Just because we haven't seen it before... this code
# uses the doctest module to check the test cases in
# the function's docstring.  If they match reality,
# the script produces no output.
def _test():
    import doctest
    doctest.testmod()
if __name__ == "__main__":
    _test()

# Try introducing an error into the docstring above
# and run this program to see the output you get if
# one of the tests fails.