code: def markers(data, marker, f_tooltip=None, marker_preferred_size=32):
      """
      Draw markers
  
      :param data: data access object
      :param marker: full filename of the marker image
      :param f_tooltip: function to generate a tooltip on mouseover
      :param marker_preferred_size: size in pixel for the marker images
      """
      from geoplotlib.layers import MarkersLayer
  
      _global_config.layers.append(
          MarkersLayer(data, marker, f_tooltip, marker_preferred_size)
      )
  
imports: import base64
  import traceback
  import pyglet
  from geoplotlib.core import GeoplotlibApp
  from core import FONT_NAME
label_desc: Use image node_id 14 for calling a global function with example usage: markers(data, marker, f_tooltip, marker_preferred_size) without return types