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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_string(string):
 """ This function checks if a path was given as string, and tries to read the file and return the string. """

   truestring = string
   if string is not None:
      if '/' in string:
         if os.path.isfile(string):
            try:
               with open_(string,'r') as f:
                  truestring = ' '.join(line.strip() for line in f)
            except: pass
      if truestring.strip() == '': truestring = None
   return truestring