code: def format_dict_to_str(dict, format):
      
      result = ''
      for k, v in dict.items():
          result = result + str(k) + format + str(v) + ', '
      return result[:-2]
docs: Format a dictionary to the string, param format is a specified format rule
      such as dict = '{'name':'Sylvanas', 'gender':'Boy'}' format = '-'
      so result is 'name-Sylvanas, gender-Boy'.
  
      >>> dict = {'name': 'Sylvanas', 'gender': 'Boy'}
      >>> format_dict_to_str(dict, format='-')
      'name-Sylvanas, gender-Boy'