<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def set_value(self, value):
 """Set the value associated with the keyword"""

        if not isinstance(value, str):
            raise TypeError("A value must be a string, got %s." % value)
        self.__value = value