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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_ip(self, interface):
 """ Returns the interface's IPv4 address if device exists and has a valid ip address. Otherwise, returns an empty string """

        if interface in ni.interfaces():
            addresses = ni.ifaddresses(interface)
            if ni.AF_INET in addresses:
                return addresses[ni.AF_INET][0]["addr"]
        return ""