old_contents: #!/usr/bin/env python
  
  """
  Copyright (c) 2006-2013 sqlmap developers (http://sqlmap.org/)
  See the file 'doc/COPYING' for copying permission
  """
  
  import re
  
  from lib.core.exception import SqlmapUndefinedMethod
  
  class Syntax:
      """
      This class defines generic syntax functionalities for plugins.
      """
  
      def __init__(self):
          pass
  
      @staticmethod
      def _escape(expression, quote=True, escaper=None):
          retVal = expression
  
          if quote:
              for item in re.findall(r"'[^']*'+", expression, re.S):
                  retVal = retVal.replace(item, escaper(item[1:-1]))
          else:
              retVal = escaper(expression)
  
          return retVal
  
      @staticmethod
      def escape(expression, quote=True):
          errMsg = "'escape' method must be defined "
          errMsg += "inside the specific DBMS plugin"
          raise SqlmapUndefinedMethod(errMsg)
  
new_contents: #!/usr/bin/env python
  
  """
  Copyright (c) 2006-2013 sqlmap developers (http://sqlmap.org/)
  See the file 'doc/COPYING' for copying permission
  """
  
  import re
  
  from lib.core.exception import SqlmapUndefinedMethod
  
  class Syntax:
      """
      This class defines generic syntax functionalities for plugins.
      """
  
      def __init__(self):
          pass
  
      @staticmethod
      def _escape(expression, quote=True, escaper=None):
          retVal = expression
  
          if quote:
              for item in re.findall(r"'[^']*'+", expression, re.S):
                  _ = item[1:-1]
                  if _:
                      retVal = retVal.replace(item, escaper(_))
          else:
              retVal = escaper(expression)
  
          return retVal
  
      @staticmethod
      def escape(expression, quote=True):
          errMsg = "'escape' method must be defined "
          errMsg += "inside the specific DBMS plugin"
          raise SqlmapUndefinedMethod(errMsg)
  
subject: Fix for empty strings (previously '' was just removed)