<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def assign_unbiased_state_label(memm_list, unbiased_state):
 r""" Sets the msm label for the given list of estimated MEMM objects. Parameters memm_list : list of estimated MEMM objects The MEMM objects which shall have the msm label set. unbiased_state : int or None Index of the unbiased thermodynamic state (if present). """

    if unbiased_state is None:
        return
    for memm in memm_list:
        assert 0 <= unbiased_state < len(memm.models), "invalid state: " + str(unbiased_state)
        memm._unbiased_state = unbiased_state