docs: def psql_string(self, sql):
          """
          Evaluate the sql file (possibly multiple statements) using psql.
          """
          argv = [
              PostgresFinder.find_root() / 'psql',
              '--quiet',
              '-U', self.user,
              '-h', self.host,
              '-p', self.port,
              '-f', '-',
              self.db_name,
          ]
          popen = subprocess.Popen(argv, stdin=subprocess.PIPE)
          popen.communicate(input=sql.encode('utf-8'))
          if popen.returncode != 0:
              raise subprocess.CalledProcessError(popen.returncode, argv)