old_contents: from datetime import date, datetime
  from functools import wraps
  try:
      # PY2
      from urllib import quote_plus
  except ImportError:
      # PY3
      from urllib.parse import quote_plus
  
  # parts of URL to be omitted
  SKIP_IN_PATH = (None, '', [], ())
  
  def _escape(value):
      """
      Escape a single value of a URL string or a query parameter. If it is a list
      or tuple, turn it into a comma-separated string first.
      """
  
      # make sequences into comma-separated stings
      if isinstance(value, (list, tuple)):
          value = u','.join(value)
  
      # dates and datetimes into isoformat
      elif isinstance(value, (date, datetime)):
          value = value.isoformat()
  
      # make bools into true/false strings
      elif isinstance(value, bool):
          value = str(value).lower()
  
      # encode strings to utf-8
      if isinstance(value, (type(''), type(u''))):
          try:
              return value.encode('utf-8')
          except UnicodeDecodeError:
              # Python 2 and str, no need to re-encode
              pass
      
      return str(value)
  
  def _make_path(*parts):
      """
      Create a URL string from parts, omit all `None` values and empty strings.
      Convert lists nad tuples to comma separated values.
      """
      #TODO: maybe only allow some parts to be lists/tuples ?
      return '/' + '/'.join(
          # preserve ',' and '*' in url for nicer URLs in logs
          quote_plus(_escape(p), ',*') for p in parts if p not in SKIP_IN_PATH)
  
  # parameters that apply to all methods
  GLOBAL_PARAMS = ('pretty', )
  
  def query_params(*es_query_params):
      """
      Decorator that pops all accepted parameters from method's kwargs and puts
      them in the params argument.
      """
      def _wrapper(func):
          @wraps(func)
          def _wrapped(*args, **kwargs):
              params = kwargs.pop('params', {})
              for p in es_query_params + GLOBAL_PARAMS:
                  if p in kwargs:
                      params[p] = _escape(kwargs.pop(p))
  
              # don't treat ignore as other params to avoid escaping
              if 'ignore' in kwargs:
                  params['ignore'] = kwargs.pop('ignore')
              return func(*args, params=params, **kwargs)
          return _wrapped
      return _wrapper
  
  
  class NamespacedClient(object):
      def __init__(self, client):
          self.client = client
  
      @property
      def transport(self):
          return self.client.transport
  
new_contents: from datetime import date, datetime
  from functools import wraps
  try:
      # PY2
      from urllib import quote_plus
  except ImportError:
      # PY3
      from urllib.parse import quote_plus
  
  # parts of URL to be omitted
  SKIP_IN_PATH = (None, '', [], ())
  
  def _escape(value):
      """
      Escape a single value of a URL string or a query parameter. If it is a list
      or tuple, turn it into a comma-separated string first.
      """
  
      # make sequences into comma-separated stings
      if isinstance(value, (list, tuple)):
          value = u','.join(value)
  
      # dates and datetimes into isoformat
      elif isinstance(value, (date, datetime)):
          value = value.isoformat()
  
      # make bools into true/false strings
      elif isinstance(value, bool):
          value = str(value).lower()
  
      # encode strings to utf-8
      if isinstance(value, (type(''), type(u''))):
          try:
              return value.encode('utf-8')
          except UnicodeDecodeError:
              # Python 2 and str, no need to re-encode
              pass
      
      return str(value)
  
  def _make_path(*parts):
      """
      Create a URL string from parts, omit all `None` values and empty strings.
      Convert lists nad tuples to comma separated values.
      """
      #TODO: maybe only allow some parts to be lists/tuples ?
      return '/' + '/'.join(
          # preserve ',' and '*' in url for nicer URLs in logs
          quote_plus(_escape(p), ',*') for p in parts if p not in SKIP_IN_PATH)
  
  # parameters that apply to all methods
  GLOBAL_PARAMS = ('pretty', 'format', )
  
  def query_params(*es_query_params):
      """
      Decorator that pops all accepted parameters from method's kwargs and puts
      them in the params argument.
      """
      def _wrapper(func):
          @wraps(func)
          def _wrapped(*args, **kwargs):
              params = kwargs.pop('params', {})
              for p in es_query_params + GLOBAL_PARAMS:
                  if p in kwargs:
                      params[p] = _escape(kwargs.pop(p))
  
              # don't treat ignore as other params to avoid escaping
              if 'ignore' in kwargs:
                  params['ignore'] = kwargs.pop('ignore')
              return func(*args, params=params, **kwargs)
          return _wrapped
      return _wrapper
  
  
  class NamespacedClient(object):
      def __init__(self, client):
          self.client = client
  
      @property
      def transport(self):
          return self.client.transport
  
subject: Format is another parameter accepted by all APIs