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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 initialise_api( debug=False, host=None, key=None, proxy=None, user_agent=None, headers=None, rate_limit=True, rate_limit_callback=None, error_retry_max=None, error_retry_backoff=None, error_retry_codes=None, ):
 """Initialise the API."""

    config = cloudsmith_api.Configuration()
    config.debug = debug
    config.host = host if host else config.host
    config.proxy = proxy if proxy else config.proxy
    config.user_agent = user_agent
    config.headers = headers
    config.rate_limit = rate_limit
    config.rate_limit_callback = rate_limit_callback
    config.error_retry_max = error_retry_max
    config.error_retry_backoff = error_retry_backoff
    config.error_retry_codes = error_retry_codes

    if headers:
        if "Authorization" in config.headers:
            encoded = config.headers["Authorization"].split(" ")[1]
            decoded = base64.b64decode(encoded)
            values = decoded.decode("utf-8")
            config.username, config.password = values.split(":")

    set_api_key(config, key)
    return config