Mage registry key Already Exist Magento 1.9.2.1

Question

I have used the Observer event in my Custom module, but when i load the added event, it is showing below error message,

Mage Registry key "Observer" already exists.

I have checked the Compiler Mode, it is in Disable state.

I am using event, Any help will be much appreciated.

<global>
    <events>
        <sales_order_status_history_save_before>
            <observers>
                <auto_order_statua>
                    <class>Custom_Status_Model_Observer</class>
                    <method>implementOrderStatus</method>
                </auto_order_statua>
            </observers>
        </sales_order_status_history_save_before>
    </events>
</global>

Observer.php

class Custom_Status_Model_Observer
{

    public function implementOrderStatus(Varien_Event_Observer $observer)
    {
        //$order = $observer->getOrder();
        //$stateProcessing = $order::STATE_PROCESSING;
        //$state = $order->getState();
        mail('[email protected]', 'test', 'test');
    }

}

Answer 1

In config.xml you should change name your event as(some_unique_identifier must unique)

    <events>
        <name_of_event_in_magento>
            <observers>
                <some_unique_identifier>
                    <type>singleton</type>
                    <class>Vendor_YourModule_Model_Observer</class>
                    <method>yourMethod</method>
                </some_unique_identifier>
            </observers>
        </name_of_event_in_magento>
    </events>

Answer 2

In Config.xml

<config>
<modules>
    <Custom_Status>
        <version>0.0.1.0</version>
    </Custom_Status>
</modules>
<global>
    <models>
        <status>
            <class>Custom_Status</class>
        </status>
    </models>
    <events>
        <sales_order_status_history_save_before>
            <observers>
                <custom_status>
                    <class>Custom_Status_Model_Observer</class>
                    <method>implementOrderStatus</method>
                </custom_status>
            </observers>
        </sales_order_status_history_save_before>
    </events>
<global>