Function fpml_read 

pub(crate) fn fpml_read(text: &str) -> PyResult<PyFpmlTrade>

Reads the first trade of an FpML 5 confirmation document from its text.

The first party in the document is the reporting party: a stream it pays is a paid leg. A swaption or a cancelable swap is read as the option or callable swap it is, its swap kept as underlying(). Anything the reader does not understand — another namespace, a missing element, an element that changes the economics, an index the registry does not carry — raises ValueError naming it.