code: def get(self, filename, reset=False):
          
          if filename in self.files and not reset:
              return self.files[filename]
  
          # load a single file, and process
          files = {}
          path = os.path.join(self.source, filename)
          files[filename] = frontmatter.load(path, 
              filename=filename,
              slug=os.path.splitext(filename)[0])
  
          # call middleware
          for func in self.middleware:
              func(files, self)
  
          # cache the processed post
          self.files.update(files)
  
          # return just the post
          try:
              return files[filename]
          except KeyError:
              raise PostNotFound('{0} not found'.format(filename))
docs: Get a single processed file. Uses a cached version
          if `run` has already been called, unless `reset` is True.