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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def interval_diff(progression1, progression2, interval):
 """Return the number of half steps progression2 needs to be diminished or augmented until the interval between progression1 and progression2 is interval."""

    i = numeral_intervals[numerals.index(progression1)]
    j = numeral_intervals[numerals.index(progression2)]
    acc = 0
    if j < i:
        j += 12
    while j - i > interval:
        acc -= 1
        j -= 1
    while j - i < interval:
        acc += 1
        j += 1
    return acc