docs: def get_by_id(self, style_id, style_type = None):
          """Find style by it's unique identifier
  
          :Returns:
            Returns found style of type :class:`ooxml.doc.Style`.
          """
  
          for st in self.styles.values():
              if st:
                  if st.style_id == style_id:
                      return st
  
          if style_type:
              return self.styles.get(self.default_styles[style_type], None)
          return None