Python: read and dump dictionary to YAML preserving order

Python: read and dump dictionary to YAML preserving order

```python
import collections , yaml

_mapping_tag = yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG

def dict_representer(dumper, data):
  return dumper.represent_mapping(_mapping_tag, data.iteritems())

def dict_constructor(loader, node):
  return collections.OrderedDict(loader.construct_pairs(node))

yaml.add_representer( collections.OrderedDict , dict_representer )
yaml.add_constructor( _mapping_tag, dict_constructor )		
		
with open( yaml_filein , 'r' ) as stream:
  dict = yaml.load( stream )
  
with open( yaml_fileout , 'w' ) as outfile:
	yaml.dump( dict , outfile , default_flow_style=False )
```