code: def fill_document(doc):
      
      with doc.create(Section('A section')):
          doc.append('Some regular text and some ')
          doc.append(italic('italic text. '))
  
          with doc.create(Subsection('A subsection')):
              doc.append('Also some crazy characters: $&#{}')
docs: Add a section, a subsection and some text to the document.
  
      :param doc: the document
      :type doc: :class:`pylatex.document.Document` instance