docs: def create_gp(self):
          """ Create GnuPlot file. """
  
          nb_bams = len(self.bams)
  
          gp_parts = [
              textwrap.dedent(
                  """\
  				set log x
  				set log x2
  
  
  				#set format x "10^{{%L}}"
  				set format x2 "10^{{%L}}"
  				set x2tics
  				unset xtics
  				"""
              ),
              os.linesep.join([self._gp_style_func(i, nb_bams) for i in range(nb_bams)]),
              textwrap.dedent(
                  """\
  					set format y "%g %%"
  					set ytics
  
  					set pointsize 1.5
  
  					set grid ytics lc rgb "#777777" lw 1 lt 0 front
  					set grid x2tics lc rgb "#777777" lw 1 lt 0 front
  
  					set datafile separator "\\t"
  					set palette negative
  					"""
              ),
              os.linesep.join(self.gp_plots)
          ]
  
          gp_src = os.linesep.join(gp_parts)
          # .format(
          # 	x_lab=self.default_x_label,
          # )
  
          with open(self._gp_fn, "w+") as f:
              f.write(gp_src)