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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 create_host(self, host_id, name, ipaddr, rack_id = None):
 """ Create a host. @param host_id: The host id. @param name: Host name @param ipaddr: IP address @param rack_id: Rack id. Default None. @return: An ApiHost object """

    return hosts.create_host(self, host_id, name, ipaddr, rack_id)