code: def set_linewidth(self, w):
      self._linewidth = float(w)
      self.ctx.set_line_width(self.renderer.points_to_pixels(w))
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import gzip
  import sys
  import warnings
  import numpy
  from matplotlib.backend_bases import _Backend, FigureCanvasBase, FigureManagerBase, GraphicsContextBase, RendererBase
  from matplotlib.mathtext import MathTextParser
  from matplotlib.path import Path
  from matplotlib.transforms import Affine2D
  from matplotlib.font_manager import ttfFontProperty
label_desc: Use image node_id 11 for calling the GraphicsContextCairo obj's underlying member method code with example usage: obj.set_linewidth(w) without return types