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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 get_matrix_servers(url: str) -> List[str]: """Fetch a list of matrix servers from a text url '-' prefixes (YAML list) are cleaned. Comment lines /^\\s*#/ are ignored url: url of a text file returns: list of urls, default schema is https """

    try:
        response = requests.get(url)
        if response.status_code != 200:
            raise requests.RequestException('Response: {response!r}')
    except requests.RequestException as ex:
        raise RuntimeError(f'Could not fetch matrix servers list: {url!r} => {ex!r}') from ex

    available_servers = []
    for line in response.text.splitlines():
        line = line.strip(string.whitespace + '-')
        if line.startswith('#') or not line:
            continue
        if not line.startswith('http'):
            line = 'https://' + line  # default schema
        available_servers.append(line)
    return available_servers