A major problem with the pre-Personal Properties Securities Act (PPSA) law was that it generally had regard to the legal form of the transaction to determine its consequences, rather than it's underlying economic purpose and effect. However, a major innovation in the PPSA is that it has abolished the pre-existing distinctions based on form, in favour of a substantive, functional or substance approach to what constitutes a 'security interest' in personal property. Discuss your understanding of these twin features of the PPSA, namely the definition and scope of what is a 'security interest' under the PPSA, and what is meant by the Act's 'functional approach'?