def __init__(self, prefix=None, postfix=None, layout=None, path=None, cache=None, preprocess=None, templateclass=None, **kwargs):
        if prefix:  self.prefix = prefix
        if postfix: self.postfix = postfix
        if layout:  self.layout = layout
        if templateclass: self.templateclass = templateclass
        if path  is not None:  self.path = path
        if cache is not None:  self.cache = cache
        if preprocess is not None: self.preprocess = preprocess
        self.kwargs = kwargs
        self.templates = {}   # template_name => Template object
Initializer of Engine class.
dataset/ETHPy150Open rst2pdf/rst2pdf/rst2pdf/tenjin.py/Engine.__init__