class_docstr: Generic abstract class for the graphers
class_docstr_tok: ["Generic","abstract","class","for","the","graphers"]
code: def watermark(
      self,
      text,
      font=None,
      color=(255, 255, 255),
      opacity=0.6,
      margin=(5, 5),
  ):
      self.image = im_watermark(
          self.image, text, color=color, opacity=opacity, margin=margin
      )
  
imports: import math
  import numpy
  from timeside.core import Processor, implements, interfacedoc, abstract
  from timeside.core.processor import FixedSizeInputAdapter
  from timeside.core.api import IGrapher
  from timeside.plugins.grapher.utils import smooth, im_watermark, normalize
  import timeside.plugins.analyzer
label_desc: Use image node_id 7 for calling the Grapher obj's underlying member method code with example usage: obj.watermark(text, font, color, opacity, margin) without return types