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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 parse(self, argument):
 """Parses argument as whitespace-separated list of strings. It also parses argument as comma-separated list of strings if requested. Args: argument: string argument passed in the commandline. Returns: [str], the parsed flag value. """

    if isinstance(argument, list):
      return argument
    elif not argument:
      return []
    else:
      if self._comma_compat:
        argument = argument.replace(',', ' ')
      return argument.split()