# Expression in Literal String Interpolation (pep-0498/#supporting-full-python-expressions)
fixtures = []

a1 = f"'{'\' \''.join(fixtures)}'"
a2 = f"'{"' '".join(fixtures)}'"

# only on Python 3.5.3
a3 = f"({'|'.join(fixtures)})"
a4 = f'" "{f} '.join(fixtures)