docs: def check_platform(self, dataset):
          '''
          int platform_variable; //............................................ RECOMMENDED - a container variable storing information about the platform. If more than one, can expand each attribute into a variable. For example, platform_call_sign and platform_nodc_code. See instrument_parameter_variable for an example.
                  platform_variable:long_name = "" ; //........................ RECOMMENDED - Provide a descriptive, long name for this variable.
                  platform_variable:comment = "" ; //.......................... RECOMMENDED - Add useful, additional information here.
                  platform_variable:call_sign = "" ; //........................ RECOMMENDED - This attribute identifies the call sign of the platform.
                  platform_variable:ncei_code = ""; //......................... RECOMMENDED - This attribute identifies the NCEI code of the platform. Look at http://www.nodc.noaa.gov/cgi-bin/OAS/prd/platform to find if NCEI codes are available.
                  platform_variable:wmo_code = "";//........................... RECOMMENDED - This attribute identifies the wmo code of the platform. Information on getting WMO codes is available at http://www.wmo.int/pages/prog/amp/mmop/wmo-number-rules.html
                  platform_variable:imo_code  = "";//.......................... RECOMMENDED - This attribute identifies the International Maritime Organization (IMO) number assigned by Lloyd's register.
          '''
          # Check for the platform variable
          platforms = util.get_platform_variables(dataset)
          if not platforms:
              return Result(BaseCheck.MEDIUM,
                            False,
                            'A container variable storing information about the platform exists',
                            ['Create a variable to store the platform information'])
  
          results = []
          for platform in platforms:
              test_ctx = TestCtx(BaseCheck.MEDIUM, 'Recommended attributes for platform variable {}'.format(platform))
              pvar = dataset.variables[platform]
              test_ctx.assert_true(getattr(pvar, 'long_name', '') != '', 'long_name attribute should exist and not be empty')
              if hasattr(pvar, 'comment'):
                  test_ctx.assert_true(getattr(pvar, 'comment', '') != '', 'comment attribute should not be empty if specified')
              # We only check to see if nodc_code, wmo_code and imo_code are empty. They are only recommended if they exist for the platform.
              found_identifier = False
              if hasattr(pvar, 'ncei_code'):
                  test_ctx.assert_true(getattr(pvar, 'ncei_code', '') != '', 'ncei_code should not be empty if specified')
                  found_identifier = True
              if hasattr(pvar, 'wmo_code'):
                  test_ctx.assert_true(getattr(pvar, 'wmo_code', '') != '', 'wmo_code should not be empty if specified')
                  found_identifier = True
              if hasattr(pvar, 'imo_code'):
                  test_ctx.assert_true(getattr(pvar, 'imo_code', '') != '', 'imo_code should not be empty if specified')
                  found_identifier = True
              if hasattr(pvar, 'call_sign'):
                  test_ctx.assert_true(getattr(pvar, 'call_sign', '') != '', 'call_sign attribute should not be empty if specified')
                  found_identifier = True
              test_ctx.assert_true(found_identifier, 'At least one attribute should be defined to identify the platform: ncei_code, wmo_code, imo_code, call_sign.')
              results.append(test_ctx.to_result())
  
          return results