Add comment, docstring and format code

Signed-off-by: Philippe Ombredanne <[email protected]>

Author: pombredanne

src/licensedcode/models.py

@@ -107,8 +107,8 @@ class License(object):
 
     # if this is a license exception, the license key this exception applies to
     is_exception = __attrib(default=False)
-    
-    #if the license falls in unknwon category then this flag should be set to true
+
+    # if the license falls in unknwon category then this flag should be set to true
     is_unknown = __attrib(default=False)
     # SPDX key for SPDX licenses
     spdx_license_key = __attrib(default=None)
@@ -343,7 +343,7 @@ def validate(licenses, verbose=False, no_dupe_urls=False):
                 )
             if not lic.owner:
                 error('No owner')
-                
+
             if lic.is_unknown:
                 if not "unknown" in lic.key:
                     error('is_unknown should not be true')
@@ -868,9 +868,14 @@ def setup(self):
 
             self.license_expression = expression.render()
             self.license_expression_object = expression
-    
+
     @property
     def has_unknown(self):
+        """
+        Return True if any of this rule licenses is an unknown license.
+        """
+        # TODO: consider using the license_expression_object and the is_unknown
+        # license flag instead
         return self.license_expression and 'unknown' in self.license_expression
 
     def validate(self, licensing=None):