'Crop data to a given time interval.
Parameters
tmin : float | None
Start time of selection in seconds.
tmax : float | None
End time of selection in seconds.
Returns
evoked : instance of Evoked
The cropped Evoked object.
Notes
Unlike Python slices, MNE time intervals include both their end points;
crop(tmin, tmax) returns the interval tmin <= t <= tmax.'

def crop(self, tmin=None, tmax=None):

    mask = _time_mask(self.times, tmin, tmax, sfreq=self.info['sfreq'])
    self.times = self.times[mask]
    self.first = int((self.times[0] * self.info['sfreq']))
    self.last = ((len(self.times) + self.first) - 1)
    self.data = self.data[:, mask]
    return self
