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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 erb(freq, Hz=None):
 """ ``B. C. J. Moore and B. R. Glasberg, "Suggested formulae for calculating auditory filter bandwidths and excitation patterns". J. Acoust. Soc. Am., 74, 1983, pp. 750-753.`` """

  if Hz is None:
    if freq < 7: # Perhaps user tried something up to 2 * pi
      raise ValueError("Frequency out of range.")
    Hz = 1
  fHz = freq / Hz
  result = 6.23e-6 * fHz ** 2 + 93.39e-3 * fHz + 28.52
  return result * Hz