'get the minor tick instances; grow as necessary'

def get_minor_ticks(self, numticks=None):

    if (numticks is None):
        numticks = len(self.get_minor_locator()())
    if (len(self.minorTicks) < numticks):
        for i in range((numticks - len(self.minorTicks))):
            tick = self._get_tick(major=False)
            self.minorTicks.append(tick)
    if (self._lastNumMinorTicks < numticks):
        protoTick = self.minorTicks[0]
        for i in range(self._lastNumMinorTicks, len(self.minorTicks)):
            tick = self.minorTicks[i]
            if self._gridOnMinor:
                tick.gridOn = True
            self._copy_tick_props(protoTick, tick)
    self._lastNumMinorTicks = numticks
    ticks = self.minorTicks[:numticks]
    return ticks
