docs: def generate_parameter_set_excel_file(self):
          """
          Generate an excel file containing the parameter sets in a format you can import into SimaPro Developer.
  
          The file will be called "ParameterSet_<ModelName>_input_file.xlsx"
          """
          
          parameter_sets = self.parameter_sets
  
          p_set = []
          filename = "ParameterSet_{}_input_file.xlsx".format(self.name)
  
          if self.save_option == 'curdir':
              base_dir = os.getcwd()
          else:
              base_dir = os.path.join(storage.simapro_dir, self.name.replace(" ", "_"))
  
          if not os.path.isdir(base_dir):
              os.mkdir(base_dir)
  
          p_set_name = os.path.join(base_dir, filename)
  
          p = self.params
          for k in p.keys():
              if p[k]['function'] is None:
                  base_dict = {'id': k, 'name': p[k]['description'], 'unit': p[k]['unit']}
  
                  for s in parameter_sets.keys():
                      base_dict[s] = parameter_sets[s][k]
  
                  p_set.append(base_dict)
              else:
                  pass
                  #print("{} is determined by a function".format(p[k]['description']))
  
          for e in self.ext_params:
              base_dict = {'id': '{}'.format(e['name']), 'type': 'external', 'name': e['description'], 'unit': ''}
  
              for s in parameter_sets.keys():
                      base_dict[s] = parameter_sets[s][e['name']]
  
              p_set.append(base_dict)
  
          df = pd.DataFrame(p_set)
  
          with pd.ExcelWriter(p_set_name, engine='xlsxwriter') as writer:
  
              ps_columns = [k for k in parameter_sets.keys()]
              #print (ps_columns)
              my_columns = ['name', 'unit', 'id']
              
              my_columns.extend(ps_columns)
              #print (my_columns)
  
              #print(df)
  
              df.to_excel(writer, sheet_name=self.name, columns=my_columns, index=False, merge_cells=False)
         
          return p_set_name