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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 _GetNetworkInfo(self, signatures_key):
 """Retrieves the network info within the signatures subkey. Args: signatures_key (dfwinreg.WinRegistryKey):
 a Windows Registry key. Returns: dict[str, tuple]: a tuple of default_gateway_mac and dns_suffix per profile identifier (GUID). """

    network_info = {}
    for category in signatures_key.GetSubkeys():
      for signature in category.GetSubkeys():
        profile_guid_value = signature.GetValueByName('ProfileGuid')
        if profile_guid_value:
          profile_guid = profile_guid_value.GetDataAsObject()
        else:
          continue

        default_gateway_mac_value = signature.GetValueByName(
            'DefaultGatewayMac')
        if default_gateway_mac_value:
          default_gateway_mac = ':'.join([
              '{0:02x}'.format(octet)
              for octet in bytearray(default_gateway_mac_value.data)])
        else:
          default_gateway_mac = None

        dns_suffix_value = signature.GetValueByName('DnsSuffix')
        if dns_suffix_value:
          dns_suffix = dns_suffix_value.GetDataAsObject()
        else:
          dns_suffix = None

        network_info[profile_guid] = (default_gateway_mac, dns_suffix)

    return network_info