def _add_batch_axis(var):
 new_var = new_var = tensor.shape_padleft(var)
 new_var.name = 'shape_padleft({})'.format(var.name)
 return new_var

def _add_batch_axis ( var ) : new_var = new_var = tensor . shape_padleft ( var ) new_var . name = 'shape_padleft({})' . format ( var . name ) return new_var
prepend a singleton axis to a tensorvariable and name it .