def _missing_co2_params(params, *args, _not=False):
"""
Checks if all co2_params are not defined.
:param params:
CO2 emission model parameters (a2, b2, a, b, c, l, l2, t, trg).
:type params: dict | lmfit.Parameters
:param _not:
If True the function checks if not all co2_params are defined.
:type _not: bool
:return:
If is missing some parameter.
:rtype: bool
"""
s = {'a', 'b', 'c', 'a2', 'b2', 'l', 'l2', 't0', 'dt', 'trg'}
if _not:
return set(params).issuperset(s)
return not set(params).issuperset(s)