Trying to display an HTML file in Anvil, how to do it?

As in the last time the map didn’t appear.
This is the code:

#Colab Side:
@anvil.server.callable
def get_map_html():
  html_string = m.get_root().render()
  return html_string

#Anvil side:
class Form1(Form1Template):
  def __init__(self, **properties):
  self.folium_placeholder = HtmlTemplate()

  def button_1_click(self, **event_args):
    """This method is called when the button is clicked"""
    self.folium_placeholder.html = anvil.server.call('get_map_html')
    self.add_component(self.folium_placeholder)
pass

When I press the button the screen turn white (like he is reading something) but the map doesn’t appear