A simple implementation of Multimap in Pyhthon, used as an example for OOP

Multimap.py

class Multimap:
    def __init__(self):
        '''Create an empty Multimap'''
        self.inner = inner

    def get(self, key):
        '''Return list of values associated with key'''
        return self.inner.get(key, [])

    def count(self, key):
        '''Returns the number of values associated with key'''
        return len(self.get(key))
  
    def put(self, key, value):
        '''Adds value to the list of values associated with key'''
        value_list = self.get(key)
        if value not in value_list:
            value_list.append(value)
            self.inner[key] = value_list

    def put_all(self, key, values):
        '''Adds all values to the list of values associated with key'''
        for v in values:
            self.put(key, v)

    def remove(self, key, value):
        '''Remove value from the list of values associated with key. 
        Returns True is the Multimap changed, False otherwise'''
        value_list = self.get(key)
        if value in value_list:
            value_list.remove(value)
            self.inner[key] = value_list
            return True
        return False

    def has_key(self, key):
        '''Returns True if key exists in the map'''
        return self.inner.has_key(key)

    def __len__(self):
        '''Returns the number of keys in the map'''
        return len(self.inner)

    def __str__(self):
        '''Converts the map to a string'''
        return str(self.inner)

    def __cmp__(self, other):
        '''Compares the map with another map'''
        return self.inner.cmp(other)

    def __contains__(self, key):
        '''Returns True if key exists in the map'''
        return self.has_key(k)

    def clear(self):
        '''Clears the map'''
        self.inner.clear()

if __name__=='__main__':        
    m = Multimap()
    m.put('Israel', 'Tel-Aviv')
    m.put('Israel', 'Jerusalem')
    m.put('France', 'Paris')
    m.put_all('England',('London', 'Manchester', 'Moscow'))
    m.remove('England', 'Moscow')
          
    print m
    print m.get('Israel')
    print 'Cities of England:', m['England']