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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 init_from_env(self):
 """ Initialize this node from environment. If we're a leaf node, i.e., a node containing a dictionary that consist of a 'default' key, compute our env variable and initialize our value from the environment. Otherwise, init our children. """


        if 'default' in self.node:
            env_var = self.__to_env_var__().upper()
            if self.has_value():
                env_val = self.node['value']
            else:
                env_val = self.node['default']
            env_val = os.getenv(env_var, to_yaml(env_val))
            try:
                self.node['value'] = yaml.load(
                    str(env_val), Loader=ConfigLoader)
            except ValueError:
                self.node['value'] = env_val
        else:
            if isinstance(self.node, dict):
                for k in self.node:
                    self[k].init_from_env()