: user@debian:~/devel/dev3; cat modtree.py
#!/usr/bin/python
import sys

def main((_, modname,)):
    showed = set()
    for depth, name, filename in mod_tree(__import__(modname)):
        print ' ' * 4 * depth, name, filename if name not in showed else ''
        showed.add(name)

def mod_tree(mod, seen=set()):
    yield 0, mod.__name__, getattr(mod, '__file__', None)
    if mod not in seen:
        seen.add(mod)
        for item in ((depth+1, name, filename)
                for submod in (getattr(mod, dep) for dep in dir(mod))
                if type(submod) is type(mod)
                for depth, name, filename in mod_tree(submod, seen)):
            yield item

if __name__ == '__main__':
    main(sys.argv)
: user@debian:~/devel/dev3; ./modtree.py email.parser
 email /usr/lib/python2.7/email/__init__.pyc
     email._parseaddr /usr/lib/python2.7/email/_parseaddr.pyc
         calendar /usr/lib/python2.7/calendar.pyc
             locale /usr/lib/python2.7/locale.pyc
                 encodings /usr/lib/python2.7/encodings/__init__.pyc
                     __builtin__ None
                     encodings.aliases /usr/lib/python2.7/encodings/aliases.pyc
                     codecs /usr/lib/python2.7/codecs.pyc
                         __builtin__
                         sys None
                     encodings.utf_8 /usr/lib/python2.7/encodings/utf_8.pyc
                         codecs
                 functools /usr/lib/python2.7/functools.pyc
                 operator None
                 re /usr/lib/python2.7/re.pyc
                     copy_reg /usr/lib/python2.7/copy_reg.pyc
                     sre_compile /usr/lib/python2.7/sre_compile.pyc
                         _sre None
                         sre_parse /usr/lib/python2.7/sre_parse.pyc
                             sys
                         sys
                     sre_parse
                     sys
                 sys
             datetime /usr/lib/python2.7/lib-dynload/datetime.so
             sys
         time None
     email.base64mime /usr/lib/python2.7/email/base64mime.pyc
     email.charset /usr/lib/python2.7/email/charset.pyc
         codecs
         email
         email.errors /usr/lib/python2.7/email/errors.pyc
     email
     email.encoders /usr/lib/python2.7/email/encoders.pyc
         base64 /usr/lib/python2.7/base64.pyc
             binascii None
             re
             struct /usr/lib/python2.7/struct.pyc
     email.errors
     email.feedparser /usr/lib/python2.7/email/feedparser.pyc
         email.errors
         email.message /usr/lib/python2.7/email/message.pyc
             binascii
             email
             email.errors
             re
             email.utils /usr/lib/python2.7/email/utils.pyc
                 base64
                 os /usr/lib/python2.7/os.pyc
                     UserDict /usr/lib/python2.7/UserDict.pyc
                         _abcoll /usr/lib/python2.7/_abcoll.pyc
                             sys
                     copy_reg
                     errno None
                     posixpath /usr/lib/python2.7/posixpath.pyc
                         genericpath /usr/lib/python2.7/genericpath.pyc
                             os
                             stat /usr/lib/python2.7/stat.pyc
                         os
                         stat
                         sys
                         warnings /usr/lib/python2.7/warnings.pyc
                             linecache /usr/lib/python2.7/linecache.pyc
                                 os
                                 sys
                             sys
                             types /usr/lib/python2.7/types.pyc
                     sys
                 random /usr/lib/python2.7/random.pyc
                     hashlib /usr/lib/python2.7/hashlib.pyc
                         _hashlib /usr/lib/python2.7/lib-dynload/_hashlib.so
                     _random None
                 re
                 socket /usr/lib/python2.7/socket.pyc
                     _socket None
                     _ssl /usr/lib/python2.7/lib-dynload/_ssl.so
                     errno
                     os
                     sys
                     warnings
                 time
                 urllib /usr/lib/python2.7/urllib.pyc
                     base64
                     os
                     socket
                     ssl /usr/lib/python2.7/ssl.pyc
                         _ssl
                         base64
                         errno
                         textwrap /usr/lib/python2.7/textwrap.pyc
                             re
                             string /usr/lib/python2.7/string.pyc
                                 re
                     string
                     sys
                     time
                 warnings
             uu /usr/lib/python2.7/uu.pyc
                 binascii
                 os
                 sys
             warnings
         re
     email.iterators /usr/lib/python2.7/email/iterators.pyc
         sys
     email.message
     email.mime /usr/lib/python2.7/email/mime/__init__.pyc
     email.parser /usr/lib/python2.7/email/parser.pyc
         warnings
     email.quoprimime /usr/lib/python2.7/email/quoprimime.pyc
         re
     sys
     email.utils
: user@debian:~/devel/dev3;