(self, tracker, *fields, state=None)
:param tracker: FieldInstanceTracker instance to be reset after
            context exit
        :param fields: a list of field names to be tracked in current context
        :param state: shared state dict used to count number of field
            occurrences in context stack.

        On context enter each field mentioned in `fields` has +1 in shared
        state, and on exit it receives -1. Fields that have zero after context
        exit are reset in tracker instance.
:param tracker: FieldInstanceTracker instance to be reset after
            context exit
        :param fields: a list of field names to be tracked in current context
        :param state: shared state dict used to count number of field
            occurrences in context stack.
: param tracker : FieldInstanceTracker instance to be reset after context exit : param fields : a list of field names to be tracked in current context : param state : shared state dict used to count number of field occurrences in context stack .
def __init__(self, tracker, *fields, state=None):
        """
        :param tracker: FieldInstanceTracker instance to be reset after
            context exit
        :param fields: a list of field names to be tracked in current context
        :param state: shared state dict used to count number of field
            occurrences in context stack.

        On context enter each field mentioned in `fields` has +1 in shared
        state, and on exit it receives -1. Fields that have zero after context
        exit are reset in tracker instance.
        """
        if state is None:
            state = {}
        self.tracker = tracker
        self.fields = fields
        self.state = state
def __init__ ( self , tracker , * fields , state = None ) : if state is None : state = { } self . tracker = tracker self . fields = fields self . state = state