code: def remove_initial_spaces_and_mark_message_lines(lines):
      
      i = 0
      while i < len(lines):
          lines[i] = lines[i].lstrip(' ')
          i += 1
      return mark_message_lines(lines)
docs: Removes the initial spaces in each line before marking message lines.
  
      This ensures headers can be identified if they are indented with spaces.