code: def _separate_header_and_content(self, text_lines):
          
          no_more_header = False
          expr_metadata = re.compile(r'^#\+[a-zA-Z]+:.*')
          header = []
          content = []
          for line in text_lines:
              metadata = expr_metadata.match(line)
              if metadata and not no_more_header:
                  header.append(line)
              else:
                  no_more_header = True
                  content.append(line)
          return header, content
docs: From a given Org text, return the header separate from the content.
          The given text must be separate line by line and be a list.
          The return is a list of two items: header and content.
          Theses two items are text separate line by line in format of a list
          Keyword Arguments:
          text_lines -- A list, each item is a line of the texte
          Return:
          [
            header   -- A list, each item is a line of the texte
            content  -- A list, each item is a line of the texte
          ]