'Given a session label and a window size, returns a list of sessions
of size `count` + 1, that either starts with the given session
(if `count` is positive) or ends with the given session (if `count` is
negative).
Parameters
session_label: pd.Timestamp
The label of the initial session.
count: int
Defines the length and the direction of the window.
Returns
pd.DatetimeIndex
The desired sessions.'

def sessions_window(self, session_label, count):

    start_idx = self.schedule.index.get_loc(session_label)
    end_idx = (start_idx + count)
    return self.all_sessions[min(start_idx, end_idx):(max(start_idx, end_idx) + 1)]
