code: def _init_a(D):
      '''Initial guess for Dirichlet alpha parameters given data D'''
      E = D.mean(axis=0)
      E2 = (D**2).mean(axis=0)
      return ((E[0] - E2[0])/(E2[0]-E[0]**2)) * f _init_a(D):
      '''Initial guess for Dirichlet alpha parameters given data D'''
      E = D.mean(axis=0)
      E2 = (D**2).mean(axis=0)
      return ((E[0] - E2[0])/(E2[0]-E[0]**2)) * E
docs: Initial guess for Dirichlet alpha parameters given data D