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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 __import_vars(self, env_file):
 """Actual importing function."""

        with open(env_file, "r") as f:  # pylint: disable=invalid-name
            for line in f:
                try:
                    line = line.lstrip()
                    if line.startswith('export'):
                        line = line.replace('export', '', 1)
                    key, val = line.strip().split('=', 1)
                except ValueError:  # Take care of blank or comment lines
                    pass
                else:
                    if not callable(val):
                        if self.verbose_mode:
                            if key in self.app.config:
                                print(
                                    " * Overwriting an existing config var:"
                                    " {0}".format(key))
                            else:
                                print(
                                    " * Setting an entirely new config var:"
                                    " {0}".format(key))
                        self.app.config[key] = re.sub(
                            r"\A[\"']|[\"']\Z", "", val)