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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 is_github_ip(ip_str):
 """Verify that an IP address is owned by GitHub."""

    if isinstance(ip_str, bytes):
        ip_str = ip_str.decode()

    ip = ipaddress.ip_address(ip_str)
    if ip.version == 6 and ip.ipv4_mapped:
        ip = ip.ipv4_mapped

    for block in load_github_hooks():
        if ip in ipaddress.ip_network(block):
            return True
    return False