title: Can't import * from sqlalchemy.ext.declarative
body: <p>If I try to execute <code>from sqlalchemy.ext.declarative import *</code> it fails. I've tried do uninstall package with <code>pip uninstall sqlalchemy</code>  and reinstall it again. I've tried removed the version from the Ubuntu repositary (the <code>python-sqlalchemy</code>-package) but it wasn't installed. I've got to a clean directory and tried the same command. Still don't work. This is both with sqlalchemy 0.7.8 and 0.7.9.</p>
  
  <p>This is the traceback:</p>
  
  <pre><code>In [1]: from sqlalchemy.ext.declarative import *
  ---------------------------------------------------------------------------
  AttributeError                            Traceback (most recent call last)
  /home/nine/slask/&lt;ipython-input-1-7f210e4ec48b&gt; in &lt;module&gt;()
  ----&gt; 1 from sqlalchemy.ext.declarative import *
  
  /usr/local/lib/python2.7/dist-packages/sqlalchemy/ext/declarative/__init__.py in &lt;module&gt;()
     1252 """
     1253
  -&gt; 1254 from .api import declarative_base, synonym_for, comparable_using, \
     1255     instrument_declarative, ConcreteBase, AbstractConcreteBase, \
     1256     DeclarativeMeta, DeferredReflection, has_inherited_table,\
  
  /usr/local/lib/python2.7/dist-packages/sqlalchemy/ext/declarative/api.py in &lt;module&gt;()
      101
      102
  --&gt; 103 class declared_attr(interfaces._MappedAttribute, property):
      104     """Mark a class-level method as representing the definition of
      105     a mapped property or special declarative member name.
  
  AttributeError: 'module' object has no attribute '_MappedAttribute'
  </code></pre>
  
  <p>For the record, I'm running Ubuntu 12.04.</p>