def sum_unit_fractions_from(m, n):
    """
    What comes in:  Two positive integers m and n with m <= n.
    What goes out:  Returns the sum:
      1/m + 1/(m+1) + 1/(m+2) + ... + 1/n.
    Side effects:   None.
    Examples:
      -- sum_unit_fractions_from(6, 9) returns
            1/6 + 1/7 + 1/8 + 1/9
         which is about 0.545635
      -- sum_unit_fractions_from(10, 9000)  returns about  6.853
    """
    # -------------------------------------------------------------------------
    # DONE: 9. Implement and test this function.
    #   Note that you should write its TEST function first (above).
    #
    # IMPORTANT: As in previous problems in this session,
    #   you must NOT use the 2 or 3-parameter versions
    #   of the RANGE expression, if you happen to know them.
    # -------------------------------------------------------------------------

    total = 0
    for k in range(n-m+1):
        total = total+1/(m+k)
    return total