How to use the pyfaidx.cli.Counter function in pyfaidx

def copy(self):
        'Like dict.copy() but returns a Counter instance instead of a dict.'
        return Counter(self)

def __sub__(self, other):
        ''' Subtract count, but keep only results with positive counts.

        '''
        if not isinstance(other, Counter):
            return NotImplemented
        result = Counter()
        for elem in set(self) | set(other):
            newcount = self[elem] - other[elem]
            if newcount > 0:
                result[elem] = newcount
        return result

def __sub__(self, other):
        ''' Subtract count, but keep only results with positive counts.

        '''
        if not isinstance(other, Counter):
            return NotImplemented
        result = Counter()
        for elem in set(self) | set(other):
            newcount = self[elem] - other[elem]
            if newcount > 0:
                result[elem] = newcount
        return result

def __and__(self, other):
        ''' Intersection is the minimum of corresponding counts.

        '''
        if not isinstance(other, Counter):
            return NotImplemented
        _min = min
        result = Counter()
        if len(self) < len(other):
            self, other = other, self
        for elem in filter(self.__contains__, other):
            newcount = _min(self[elem], other[elem])
            if newcount > 0:
                result[elem] = newcount
        return result

def __add__(self, other):
        '''Add counts from two counters.

        '''
        if not isinstance(other, Counter):
            return NotImplemented
        result = Counter()
        for elem in set(self) | set(other):
            newcount = self[elem] + other[elem]
            if newcount > 0:
                result[elem] = newcount
        return result

def __or__(self, other):
        '''Union is the maximum of value in either of the input counters.

        '''
        if not isinstance(other, Counter):
            return NotImplemented
        _max = max
        result = Counter()
        for elem in set(self) | set(other):
            newcount = _max(self[elem], other[elem])
            if newcount > 0:
                result[elem] = newcount
        return result