old_contents: #//===--- MirrorCommon.py -------------------------------------*- python -*-===//
  #//
  #// This source file is part of the Swift.org open source project
  #//
  #// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
  #// Licensed under Apache License v2.0 with Runtime Library Exception
  #//
  #// See http://swift.org/LICENSE.txt for license information
  #// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
  #//
  #//===----------------------------------------------------------------------===//
  # This file contains utility functions that are used by the gyb template files
  # that generate Mirrors for the Swift Standard Library.
  # If you edit this, make sure to also accordingly tweak the actual template files.
  
  def getDisposition(disp=None):
    if disp == None:
      return '.Aggregate'
    if len(disp) == 0 or disp[0] != '.':
      disp = '.' + disp
    return disp
  
  def _getGenericArgStrings(genericArgs=None,genericConstraints=None):
    if genericArgs == None:
      return ('','')
    genericArgString = ''
    first = True
    for arg in genericArgs:
      if not first:
        genericArgString  = genericArgString + ','
      first = False
      genericArgString = genericArgString + arg
    if genericConstraints == None:
      genericConstraintString = genericArgString
    else:
      genericConstraintString = ''
      first = True
      for arg in genericArgs:
        if not first:
          genericConstraintString = genericConstraintString + ','
        first = False
        genericConstraintString = genericConstraintString + arg
        if arg in genericConstraints:
          cons = genericConstraints[arg]
          genericConstraintString = genericConstraintString + ' : ' + cons
    genericArgString = '<' + genericArgString + '>'
    genericConstraintString = '<' + genericConstraintString + '>'
    return (genericArgString,genericConstraintString)
  
  def getGenericArgString(genericArgs=None,genericConstraints=None):
    return _getGenericArgStrings(genericArgs,genericConstraints)[0]
  
  def getGenericConstraintString(genericArgs=None,genericConstraints=None):
    return _getGenericArgStrings(genericArgs,genericConstraints)[1]
  
  
new_contents: #//===--- MirrorCommon.py -------------------------------------*- python -*-===//
  #//
  #// This source file is part of the Swift.org open source project
  #//
  #// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
  #// Licensed under Apache License v2.0 with Runtime Library Exception
  #//
  #// See http://swift.org/LICENSE.txt for license information
  #// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
  #//
  #//===----------------------------------------------------------------------===//
  # This file contains utility functions that are used by the gyb template files
  # that generate Mirrors for the Swift Standard Library.
  # If you edit this, make sure to also accordingly tweak the actual template files.
  
  def getDisposition(disp=None):
    if disp is None:
      return '.Aggregate'
    if len(disp) == 0 or disp[0] != '.':
      disp = '.' + disp
    return disp
  
  def _getGenericArgStrings(genericArgs=None, genericConstraints=None):
    if genericArgs is None:
      return ('','')
    genericArgString = ''
    first = True
    for arg in genericArgs:
      if not first:
        genericArgString = genericArgString + ','
      first = False
      genericArgString = genericArgString + arg
    if genericConstraints is None:
      genericConstraintString = genericArgString
    else:
      genericConstraintString = ''
      first = True
      for arg in genericArgs:
        if not first:
          genericConstraintString = genericConstraintString + ','
        first = False
        genericConstraintString = genericConstraintString + arg
        if arg in genericConstraints:
          cons = genericConstraints[arg]
          genericConstraintString = genericConstraintString + ' : ' + cons
    genericArgString = '<' + genericArgString + '>'
    genericConstraintString = '<' + genericConstraintString + '>'
    return (genericArgString, genericConstraintString)
  
  def getGenericArgString(genericArgs=None, genericConstraints=None):
    return _getGenericArgStrings(genericArgs, genericConstraints)[0]
  
  def getGenericConstraintString(genericArgs=None, genericConstraints=None):
    return _getGenericArgStrings(genericArgs, genericConstraints)[1]
  
  
subject: Use "is None" and add space after comma