PYTHON-946 - Allow fields to be any sequence.

Author: jaraco

pymongo/helpers.py

@@ -270,7 +270,7 @@ def _check_write_command_response(results):
 
 
 def _fields_list_to_dict(fields, option_name):
- """Takes a list of field names and returns a matching dictionary.
+ """Takes a sequence of field names and returns a matching dictionary.
 
  ["a", "b"] becomes {"a": 1, "b": 1}
 
@@ -280,15 +280,13 @@ def _fields_list_to_dict(fields, option_name):
  """
  if isinstance(fields, collections.Mapping):
  return fields
- elif isinstance(fields, list):
- as_dict = {}
- for field in fields:
- if not isinstance(field, string_type):
- raise TypeError("%s must be a list of key names, each an "
- "instance of %s" % (option_name,
- string_type.__name__))
- as_dict[field] = 1
- return as_dict
- else:
- raise TypeError("%s must be a mapping or "
- "list of key names" % (option_name,))
+
+ if isinstance(fields, collections.Sequence):
+ if not all(isinstance(field, string_type) for field in fields):
+ raise TypeError("%s must be a list of key names, each an "
+ "instance of %s" % (option_name,
+ string_type.__name__))
+ return dict.fromkeys(fields, 1)
+
+ raise TypeError("%s must be a mapping or "
+ "list of key names" % (option_name,))