code: def _energy_coeffs(m1, m2, chi1, chi2):
      
      mtot = m1 + m2
      eta = m1*m2 / (mtot*mtot)
      chi = (m1*chi1 + m2*chi2) / mtot
      chisym = (chi1 + chi2) / 2.
      beta = (113.*chi - 76.*eta*chisym)/12.
      sigma12 = 79.*eta*chi1*chi2/8.
      sigmaqm = 81.*m1*m1*chi1*chi1/(16.*mtot*mtot) \
              + 81.*m2*m2*chi2*chi2/(16.*mtot*mtot)
  
      energy0 = -0.5*eta
      energy2 = -0.75 - eta/12.
      energy3 = 0.
      energy4 = -3.375 + (19*eta)/8. - pow(eta,2)/24.
      energy5 = 0.
      energy6 = -10.546875 - (155*pow(eta,2))/96. - (35*pow(eta,3))/5184. \
                  + eta*(59.80034722222222 - (205*pow(lal.PI,2))/96.)
  
      energy3 += (32*beta)/113. + (52*chisym*eta)/113.
  
      energy4 += (-16*sigma12)/79. - (16*sigmaqm)/81.
      energy5 += (96*beta)/113. + ((-124*beta)/339. - (522*chisym)/113.)*eta \
                  - (710*chisym*pow(eta,2))/339.
  
      return (energy0, energy2, energy3, energy4, energy5, energy6)
docs: Return the center-of-mass energy coefficients up to 3.0pN (2.5pN spin)