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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def register(classname, cls):
 """Add a class to the registry of serializer classes. When a class is registered, an entry for both its classname and its full, module-qualified path are added to the registry. Example: :: class MyClass: pass register('MyClass', MyClass) # Registry: # { # 'MyClass': [path.to.MyClass], # 'path.to.MyClass': [path.to.MyClass], # } """

    # Module where the class is located
    module = cls.__module__
    # Full module path to the class
    # e.g. user.schemas.UserSchema
    fullpath = '.'.join([module, classname])
    # If the class is already registered; need to check if the entries are
    # in the same module as cls to avoid having multiple instances of the same
    # class in the registry
    if classname in _registry and not \
            any(each.__module__ == module for each in _registry[classname]):
        _registry[classname].append(cls)
    elif classname not in _registry:
        _registry[classname] = [cls]

    # Also register the full path
    if fullpath not in _registry:
        _registry.setdefault(fullpath, []).append(cls)
    else:
        # If fullpath does exist, replace existing entry
        _registry[fullpath] = [cls]
    return None