Three global value chain (GVC) decompositions are implemented. 
    The Leontief decomposition derives the value added origin of exports by 
    country and industry as in Hummels, Ishii and Yi (2001). The Koopman, 
    Wang and Wei (2014) decomposition splits country-level exports into 9 
    value added components, and the Wang, Wei and Zhu (2013) decomposition 
    splits bilateral exports into 16 value added components. Various GVC 
    indicators based on these decompositions are computed in the 
    complimentary 'gvc' package. 
    --- References: ---
    Hummels, D., Ishii, J., & Yi, K. M. (2001). The nature and growth of 
       vertical specialization in world trade. Journal of international 
       Economics, 54(1), 75-96.
    Koopman, R., Wang, Z., & Wei, S. J. (2014). Tracing value-added and double 
       counting in gross exports. American Economic Review, 104(2), 459-94.
    Wang, Z., Wei, S. J., & Zhu, K. (2013). Quantifying international production 
       sharing at the bilateral and sector levels (No. w19677). 
       National Bureau of Economic Research.

Empirical Bayes methods for learning prior distributions from data.
    An unknown prior distribution (g) has yielded (unobservable) parameters, each of
    which produces a data point from a parametric exponential family (f). The goal
    is to estimate the unknown prior ("g-modeling") by deconvolution and Empirical
    Bayes methods. Details and examples are in the paper by Narasimhan and Efron
    (2020, <doi:10.18637/jss.v094.i11>).

Retrieves code comment decorations for C++
    languages of the form '\\ [[xyz]]', which are used for automated
    wrapping of C++ functions.

DECORATE (Diverse Ensemble Creation by Oppositional Relabeling
    of Artificial Training Examples) builds an ensemble of J48 trees by recursively
    adding artificial samples of the training data ("Melville, P., & Mooney, R. J. (2005) <DOI:10.1016/j.inffus.2004.04.001>").

A decorator is a function that receives a function, extends
    its behaviour, and returned the altered function. Any caller that uses
    the decorated function uses the same interface as it were the
    original, undecorated function. Decorators serve two primary uses: (1)
    Enhancing the response of a function as it sends data to a second
    component; (2) Supporting multiple optional behaviours. An example of
    the first use is a timer decorator that runs a function, outputs its
    execution time on the console, and returns the original function's
    result. An example of the second use is input type validation
    decorator that during running time tests whether the caller has passed
    input arguments of a particular class.  Decorators can reduce
    execution time, say by memoization, or reduce bugs by adding defensive
    programming routines.