160                         ', '.join(sorted(from_stdlib[False]))))

   160                         ', '.join(sorted(from_stdlib[False]))))

   161 

   161 

   162 class CircularImport(Exception):

   162 class CircularImport(Exception):

   163     pass

   163     pass

   164 

   164 

   169 def checkmod(mod, imports):

   165 def checkmod(mod, imports):

   170     shortest = {}

   166     shortest = {}

   171     visit = [[mod]]

   167     visit = [[mod]]

   172     while visit:

   168     while visit:

   173         path = visit.pop(0)

   169         path = visit.pop(0)

   201     ...            'top.qux': ['foo']}

   197     ...            'top.qux': ['foo']}

   202     >>> print '\\n'.join(sorted(find_cycles(imports)))

   198     >>> print '\\n'.join(sorted(find_cycles(imports)))

   203     top.bar -> top.baz -> top.foo -> top.bar

   199     top.bar -> top.baz -> top.foo -> top.bar

   204     top.foo -> top.qux -> top.foo

   200     top.foo -> top.qux -> top.foo

   205     """

   201     """

   207     for mod in sorted(imports.iterkeys()):

   203     for mod in sorted(imports.iterkeys()):

   208         try:

   204         try:

   209             checkmod(mod, imports)

   205             checkmod(mod, imports)

   210         except CircularImport, e:

   206         except CircularImport, e:

   211             cycle = e.args[0]

   207             cycle = e.args[0]

   214 

   210 

   215 def _cycle_sortkey(c):

   211 def _cycle_sortkey(c):

   216     return len(c), c

   212     return len(c), c

   217 

   213 

   218 def main(argv):

   214 def main(argv):