code: def push_header(self, filename):
          
          # open file and read it all
          with open(filename, "r") as infile:
              content = infile.read()
  
          # push header
          content = self.__header + content
  
          # re-write file with the header
          with open(filename, "w") as outfile:
              outfile.write(content)
docs: Push the header to a given filename
          :param filename: the file path to push into.