defineUpRange = function() {
    return Blockly.Python.provideFunction_(
        'upRange',
        ['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ +
            '(start, stop, step):',
         '  while start <= stop:',
         '    yield start',
         '    start += abs(step)']);
  }
@fileoverview Generating Python for loop blocks.
@author q.neutron@gmail.com (Quynh Neutron)