docs: def png_as_base64_str(self, scale=1, module_color=(0, 0, 0, 255),
                            background=(255, 255, 255, 255), quiet_zone=4):
          """This method uses the png render and returns the PNG image encoded as
          base64 string. This can be useful for creating dynamic PNG images for
          web development, since no file needs to be created.
          
          Example:
              >>> code = pyqrcode.create('Are you suggesting coconuts migrate?')
              >>> image_as_str = code.png_as_base64_str(scale=5)
              >>> html_img = '<img src="data:image/png;base64,{}">'.format(image_as_str)
  
          The parameters are passed directly to the :py:meth:`png` method. Refer
          to that method's documentation for the meaning behind the parameters.
          
          .. note::
              This method depends on the pypng module to actually create the
              PNG image.
  
          """
          import io
          import base64
          
          with io.BytesIO() as virtual_file:
              self.png(file=virtual_file, scale=scale, module_color=module_color,
                       background=background, quiet_zone=quiet_zone)
              image_as_str = base64.b64encode(virtual_file.getvalue()).decode("ascii")
          return image_as_str