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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 isfile(self, path=None, client_kwargs=None, assume_exists=None):
 """ Return True if path is an existing regular file. Args: path (str):
 Path or URL. client_kwargs (dict):
 Client arguments. assume_exists (bool or None):
 This value define the value to return in the case there is no enough permission to determinate the existing status of the file. If set to None, the permission exception is reraised (Default behavior). if set to True or False, return this value. Returns: bool: True if file exists. """

        relative = self.relpath(path)
        if not relative:
            # Root always exists and is a directory
            return False

        if path[-1] != '/' and not self.is_locator(path, relative=True):
            return self.exists(path=path, client_kwargs=client_kwargs,
                               assume_exists=assume_exists)
        return False