# Τεκμηρίωση του Django - 1.10.7

# Πηγαίος κώδικας για το django.template.loaders.base

    import warnings

    from django.template import Origin, Template, TemplateDoesNotExist
    from django.utils.deprecation import RemovedInDjango20Warning
    from django.utils.inspect import func_supports_parameter

    class Loader(object):

        def __init__(self, engine):
            self.engine = engine

        def __call__(self, template_name, template_dirs=None):
            # RemovedInDjango20Warning: Allow loaders to be called like functions.
            return self.load_template(template_name, template_dirs)

        def get_template(self, template_name, template_dirs=None, skip=None):
            """
            Calls self.get_template_sources() and returns a Template object for
            the first template matching template_name. If skip is provided,
            template origins in skip are ignored. This is used to avoid recursion
            during template extending.
            """
            tried = []

            args = [template_name]
            # RemovedInDjango20Warning: Add template_dirs for compatibility with
            # old loaders
            if func_supports_parameter(self.get_template_sources, 'template_dirs'):
                args.append(template_dirs)

            for origin in self.get_template_sources(*args):
                if skip is not None and origin in skip:
                    tried.append((origin, 'Skipped'))
                    continue

                try:
                    contents = self.get_contents(origin)
                except TemplateDoesNotExist:
                    tried.append((origin, 'Source does not exist'))
                    continue
                else:
                    return Template(
                        contents, origin, origin.template_name, self.engine,
                    )

            raise TemplateDoesNotExist(template_name, tried=tried)

        def load_template(self, template_name, template_dirs=None):
            warnings.warn(
                'The load_template() method is deprecated. Use get_template() '
                'instead.', RemovedInDjango20Warning,
            )
            source, display_name = self.load_template_source(
                template_name, template_dirs,
            )
            origin = Origin(
                name=display_name,
                template_name=template_name,
                loader=self,
            )
            try:
                template = Template(source, origin, template_name, self.engine)
            except TemplateDoesNotExist:
                # If compiling the template we found raises TemplateDoesNotExist,
                # back off to returning the source and display name for the
                # template we were asked to load. This allows for correct
                # identification of the actual template that does not exist.
                return source, display_name
            else:
                return template, None

        def get_template_sources(self, template_name):
            """
            An iterator that yields possible matching template paths for a
            template name.
            """
            raise NotImplementedError(
                'subclasses of Loader must provide a get_template_sources() method'
            )

        def load_template_source(self, template_name, template_dirs=None):
            """
            RemovedInDjango20Warning: Returns a tuple containing the source and
            origin for the given template name.
            """
            raise NotImplementedError(
                'subclasses of Loader must provide a load_template_source() method'
            )

        def reset(self):
            """
            Resets any state maintained by the loader instance (e.g. cached
            templates or cached loader modules).
            """
            pass

        @property
        def supports_recursion(self):
            """
            RemovedInDjango20Warning: This is an internal property used by the
            ExtendsNode during the deprecation of non-recursive loaders.
            """
            return hasattr(self, 'get_contents')