From the ReadMe file of Li:

We tried to match the CMDs of four clusters using our stellar
population synthesis model (Yunnan model). The model uses the SSE and
BSE of Hurley to calculate the evolution of stars. Then the BaSeL
spectra library is used for translating log(g) and log(Teff) to colors
and spectra of populations. All populations adopt the IMF of Salpeter
(alpha=-2.35).

In the work, we matched CMDs by both single stellar populations (SSP)
and binary stellar populations (BSPs). The difference between them is
BSPs take the binary interactions into account.

The results derived from SSP fitting are:
M67    : t=    3.6000 Gyr Z=    0.0200 (m-M)v =    9.5800 E(B-V)=    0.0470
NGC1868: t=    0.9000 Gyr Z=    0.0100 (m-M)v =   18.5100 E(V-I)=    0.0550
NGC1805: t=    0.6000 Gyr Z=    0.0200 (m-M)v =   18.2000 E(V-I)=    0.0280
47Tuc  : t=   13.6000 Gyr Z=    0.0040 (m-M)v =   13.2100 E(B-V)=    0.0500

The results derived from BSP fitting are:
M67    : t=    3.2000 Gyr Z=    0.0200 (m-M)v =    9.5800 E(B-V)=    0.0470
NGC1868: t=    1.0000 Gyr Z=    0.0100 (m-M)v =   18.5100 E(V-I)=    0.0550
NGC1805: t=    0.2000 Gyr Z=    0.0200 (m-M)v =   18.2000 E(V-I)=    0.0280
47Tuc  : t=   13.6000 Gyr Z=    0.0040 (m-M)v =   13.2100 E(B-V)=    0.0500


The results derived from LF fitting with both SSPs and BSPs are:
NGC1868: t=    0.2000 Gyr
NGC1805: t=    0.2000 Gyr
(the metallicities derived from SSP and BSP fitting are different)


The results derived from spectra fitting with SSPs are:
M67    : t=   14.0000 Gyr Z=    0.004
NGC1868: t=    1.6000 Gyr Z=    0.0003
NGC1805: t=    0.1000 Gyr Z=    0.0300


Models vs. data (generated by S.C. Trager):
47 Tuc
M67
NGC 1805
NGC 1868
In all plots, the upper left panel is the observed data.  The upper right panel has the SSP model overlaid in green open points.  The lower left panel has the BSP model overlaid in red open points.

47 Tuc SSP model
47 Tuc BSP model
M67 SSP model
M67 BSP model
NGC 1805 SSP model
NGC 1805 BSP model
NGC 1868 SSP model
NGC 1868 BSP model