code: def from_file(cls, filename, **kwargs):
          
          filename = os.path.expanduser(filename)
          if not os.path.isfile(filename):
              raise exceptions.PyKubeError("Configuration file {} not found".format(filename))
          with open(filename) as f:
              doc = yaml.safe_load(f.read())
          self = cls(doc, **kwargs)
          self.filename = filename
          return self
docs: Creates an instance of the KubeConfig class from a kubeconfig file.
  
          :Parameters:
             - `filename`: The full path to the configuration file