code: def a_list(label=None, kwargs=None, attributes=None):
      """Return assembled DOT a_list string.
  
      >>> a_list('spam', {'spam': None, 'ham': 'ham ham', 'eggs': ''})
      'label=spam eggs="" ham="ham ham"'
      """
      result = ["label=%s" % quote(label)] if label is not None else []
      if kwargs:
          items = [
              "%s=%s" % (quote(k), quote(v))
              for k, v in tools.mapping_items(kwargs)
              if v is not None
          ]
          result.extend(items)
      if attributes:
          if hasattr(attributes, "items"):
              attributes = tools.mapping_items(attributes)
          items = [
              "%s=%s" % (quote(k), quote(v))
              for k, v in attributes
              if v is not None
          ]
          result.extend(items)
      return " ".join(result)
  
file_path: catboost/contrib/python/graphviz/py2/graphviz/lang.py
imports: import collections
  import functools
  import re
  from .None import _compat
  from .None import tools
label_desc: Use image node_id 3 for calling a global function with example usage: a_list(label, kwargs, attributes) and returns: str