Added NumGet returning pair<it,expected<int>>

Trere is a problem on the evaluation of noexcept(value(rhs))

//../../../boost/expected/expected.hpp:140:91: error: called object
type 'value_type' (aka 'long') is not a function or function pointer
//BOOST_CONSTEXPR expected(const value_type& rhs)
BOOST_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(value(rhs)))