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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 _salt_send_event(opaque, conn, data):
    '''
    Convenience function adding common data to the event and sending it
    on the salt event bus.

    :param opaque: the opaque data that is passed to the callback.
                   This is a dict with 'prefix', 'object' and 'event' keys.
    :param conn: libvirt connection
    :param data: additional event data dict to send
    '''
    tag_prefix = opaque['prefix']
    object_type = opaque['object']
    event_type = opaque['event']

    # Prepare the connection URI to fit in the tag
    # qemu+ssh://user@host:1234/system -> qemu+ssh/user@host:1234/system
    uri = urlparse(conn.getURI())
    uri_tag = [uri.scheme]
    if uri.netloc:
        uri_tag.append(uri.netloc)
    path = uri.path.strip('/')
    if path:
        uri_tag.append(path)
    uri_str = "/".join(uri_tag)

    # Append some common data
    all_data = {
        'uri': conn.getURI()
    }
    all_data.update(data)

    tag = '/'.join((tag_prefix, uri_str, object_type, event_type))

    # Actually send the event in salt
    if __opts__.get('__role') == 'master':
        salt.utils.event.get_master_event(
            __opts__,
            __opts__['sock_dir']).fire_event(all_data, tag)
    else:
        __salt__['event.send'](tag, all_data)