Compatibility function returns None

Hi, I have vasprun.xml obtained from VASP. I want to apply correction by MaterialsProject2020Compatibility function, but it results in None. Can anyone let me know how to fix it? Thank you in advance.

vasprun = Vasprun("data/vasprun.xml")
entry = vasprun.get_computed_entry(inc_structure=False)

compatibility = MaterialsProject2020Compatibility(compat_type="GGA")
entry1 = compatibility.process_entry(entry)

It returns

Energy (Uncorrected)     = -291.9313 eV (-7.2983  eV/atom)
Correction               = 0.0000    eV (0.0000   eV/atom)
Energy (Final)           = -291.9313 eV (-7.2983  eV/atom)
Energy Adjustments: