An oversimplified explanation of the code is as follows:
protected function checkData( $item = null )
A protected function can only be accessed from within the class only.
The function of checkData is to see if it it contains a value, in this case a licence key (license_data), or not (empty/no license key added.)
if ( empty( $this->license_data ) )
Checks to see “if” license_data is empty or not. When you don’t add your license key, the values is empty (null.)
return false;
Since the license_data doesn’t contain any value (null) this part returns a false, thus disabling the possibility to use the plugin or theme in question.
When we switch “false” to “true”, we’re basically fooling the code by asking it to return true when the license_data doesn’t contain a value. Thus we’re “switching” the logic.
}
The end bracket used to encapsulate the function.
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