title: How can I get pyyaml.safe_load() to handle python/unicode tag?
body: <p>We've a situation where we use yaml to pass some data in specific situations. We'd like to roll it out further, and I'm starting we should be using yaml.safe_load(). There is nothing particularly complicated about the yaml, but I notice a particular feature when the original string is unicode. For example:</p>
  
  <pre><code>&gt;&gt;&gt; x = u"hello"
  &gt;&gt;&gt; x
  u'hello'
  &gt;&gt;&gt; yaml.dump(x)
  "!!python/unicode 'hello'\n"
  </code></pre>
  
  <p>If I try and read this in, I get an exception:</p>
  
  <pre><code>...
    File "f:\users\---\PyYAML-3.11-py2.7-win-amd64.egg.tmp\yaml\constructor.py", line 414, in construct_undefined yaml.constructor.ConstructorError: could not determine a constructor for the tag 'tag:yaml.org,2002:python/unicode'
    in "&lt;string&gt;", line 1, column 1:
      !!python/unicode 'hello'
  </code></pre>
  
  <p>I've seen it is possible to indicate classes are supported on safe_load, but this is not a user class. I could switch to using safe_dump(), but that would not work where the data has been written by an older version of one tool and read by a newer version of another (say).</p>
  
  <p>So question: can I tell pyyaml that it can load python unicode strings?</p>