<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def availability_rtf() -> bool: """ Is an RTF processor available? """

    unrtf = tools['unrtf']
    if unrtf:
        return True
    elif pyth:
        log.warning("RTF conversion: unrtf missing; "
                    "using pyth (less efficient)")
        return True
    else:
        return False