def pinch(self, scale, velocity):
data = {'<STR_LIT>': scale, '<STR_LIT>': velocity}<EOL>return self._wda_req('<STR_LIT>', '<STR_LIT>', data)<EOL>
Args:
    scale (float): scale must > 0
    velocity (float): velocity must be less than zero when scale is less than 1

Example:
    pinchIn  -> scale:0.5, velocity: -1
    pinchOut -> scale:2.0, velocity: 1