code: def mirtrace_rna_categories(self):
          
  
          # Specify the order of the different possible categories
          keys = OrderedDict()
          keys['reads_mirna']      =   { 'color': '#33a02c', 'name': 'miRNA' }
          keys['reads_rrna']       =   { 'color': '#ff7f00', 'name': 'rRNA' }
          keys['reads_trna']       =   { 'color': '#1f78b4', 'name': 'tRNA' }
          keys['reads_artifact']   =   { 'color': '#fb9a99', 'name': 'Artifact' }
          keys['reads_unknown']    =   { 'color': '#d9d9d9', 'name': 'Unknown' }
  
          # Config for the plot
          config = {
              'id': 'mirtrace_rna_categories_plot',
              'title': 'miRTrace: RNA Categories',
              'ylab': '# Reads',
              'cpswitch_counts_label': 'Number of Reads'
          }
  
          return bargraph.plot(self.summary_data, keys, config)
docs: Generate the miRTrace RNA Categories