title: Error when parsing yaml file : found character '%' that cannot start any token
body: <p>I am trying to parse data from yaml file having some expressions similar to jinaj2 template syntax, the goal is to delete or add some items to the file.</p>
  
  <p><em>AddCodesList.yaml</em></p>
  
  <pre><code>AddCodesList:
    body:
      list:
      {% for elt in customer %}
        - code: {{ elt.code }}
          name: {{ elt.name }}
          country: {{ elt.country }}
      {% endfor %}   
    result:
      json:
        responseCode: {{ responseCode }}
        responseMsg: {{ responseMsg }}
        responseData: {{ responseData }}
  </code></pre>
  
  <p><em>parseFile.py</em></p>
  
  <pre><code>import ruamel.yaml
  from ruamel.yaml.util import load_yaml_guess_indent
  
  data,indent,block_seq_indent=load_yaml_guess_indent(open('AddCodesList.yaml'), preserve_quotes=True)
  
  #delete item
  del data['body']['list']['code']
  #add new item
  data['parameters'].insert(2, 'ssl_password','xxxxxx')#create new file
  ruamel.yaml.round_trip_dump(data, open('missingCode.yaml', 'w'), explicit_start=True)
  </code></pre>
  
  <p>I have the following error when executing the parseFile.py script:</p>
  
  <pre><code>    Traceback (most recent call last):
        File "d:/workspace/TEST/manageItem.py", line 4, in &lt;module&gt;
          data, indent, block_seq_indent = load_yaml_guess_indent(open('AddCodesList.
  ...
          if self.check_token(ValueToken):
        File "C:\Python34\lib\site-packages\ruamel\yaml\scanner.py", line 1534, in ch
          self.fetch_more_tokens()
        File "C:\Python34\lib\site-packages\ruamel\yaml\scanner.py", line 269, in fet
          % utf8(ch), self.get_mark())
      ruamel.yaml.scanner.ScannerError: while scanning for the next token
      found character '%' that cannot start any token
        in "&lt;unicode string&gt;", line 4, column 6:
              {% for elt in customer %}
               ^ (line: 4)
  </code></pre>