When overridden in a derived class, reconstructs properties and internal state specific to a derived code group from the specified System.Security.SecurityElement.
CodeGroup.FromXml(System.Security.SecurityElement) cannot be overridden. If you need to deserialize members specific to a particular implementation of System.Security.Policy.CodeGroup, you must override CodeGroup.ParseXml(System.Security.SecurityElement, PolicyLevel) and deserialize your members there. When the code group is deserialized, CodeGroup.FromXml(System.Security.SecurityElement) calls CodeGroup.ParseXml(System.Security.SecurityElement, PolicyLevel) and reconstructs your members from the System.Security.SecurityElement.
This method deserializes XML created using CodeGroup.CreateXml(System.Security.SecurityElement, PolicyLevel).