code: def update_style(self, title=None,defaults=None,mappings=None, verbose=False):
          
          u=self.__url
          host=u.split("//")[1].split(":")[0]
          port=u.split(":")[2].split("/")[0]
          version=u.split(":")[2].split("/")[1]
  
          if defaults:
              defaults_=[]
              for d in defaults:
                  if d:
                      defaults_.append(d)
              defaults=defaults_
  
          if mappings:
              mappings_=[]
              for m in mappings:
                  if m:
                      mappings_.append(m)
              mappings=mappings_
  
          URL="http://"+str(host)+":"+str(port)+"/v1/styles/"+str(title)
          if verbose:
              print(URL)
              sys.stdout.flush()
  
          response = requests.get(URL).json()
  
          olddefaults=response["defaults"]
          oldmappings=response["mappings"]
  
          if mappings:
              mappings_visual_properties=[ m["visualProperty"] for m in mappings ]
              newmappings=[ m for m in oldmappings if m["visualProperty"] not in mappings_visual_properties ]
              for m in mappings:
                  newmappings.append(m)
          else:
              newmappings=oldmappings
  
          if defaults:
              defaults_visual_properties=[ m["visualProperty"] for m in defaults ]
              newdefaults=[ m for m in olddefaults if m["visualProperty"] not in defaults_visual_properties ]
              for m in defaults:
                  newdefaults.append(m)
          else:
              newdefaults=olddefaults
  
          r=requests.delete(URL)
          checkresponse(r)
  
          URL="http://"+str(host)+":"+str(port)+"/v1/styles"
          PARAMS={"title":title,\
              "defaults":newdefaults,\
              "mappings":newmappings}
          r = requests.post(url = URL, json = PARAMS)
          checkresponse(r)
docs: Updates a visual style
  
          :param title: title of the visual style
          :param defaults: a list of dictionaries for each visualProperty
          :param mappings: a list of dictionaries for each visualProperty
  
          :returns: nothing