def luminosity_to_flux(lumErg_S, dist_Mpc):
<EOL>import numpy as np<EOL>import math<EOL>distCm = dist_Mpc * MPC_2_CMS<EOL>fluxErg_cm2_S = lumErg_S / (<NUM_LIT:4> * np.pi * distCm ** <NUM_LIT:2>)<EOL>return fluxErg_cm2_S<EOL>
*Convert luminosity to a flux*

**Key Arguments:**
    - ``lumErg_S`` -- luminosity in ergs/sec
    - ``dist_Mpc`` -- distance in Mpc

**Return:**
    - ``fluxErg_cm2_S`` -- flux in ergs/cm2/s