def removeDups(aSeq):
    """Remove duplicate entries from a sequence,
    returning the results as a list.
    Preserves the ordering of retained elements.
    """
    tempDict = {}
    def isUnique(val):
        if val in tempDict:
            return False
        tempDict[val] = None
        return True

    return [val  for val in aSeq if isUnique(val)]