code: def content_children(self):
          
          text_types = {CT_RegularTextRun, CT_TextLineBreak, CT_TextField}
          return tuple(elm for elm in self if type(elm) in text_types)
docs: A sequence containing the text-container child elements of this
          ``<a:p>`` element, i.e. (a:r|a:br|a:fld).