MAINT: small cleanups for fv

- Remove an unused variable in the implementation
- Adjust some spacing in the implementation
- Use the ternary operator in tests to make them read better

Author: person142

numpy_financial/_financial.py

@@ -133,10 +133,9 @@ def fv(rate, nper, pmt, pv, when='end'):
     fv_array[zero] = -(pv[zero] + pmt[zero] * nper[zero])
 
     rate_nonzero = rate[nonzero]
-    nper_nonzero = nper[nonzero]
     temp = (1 + rate_nonzero)**nper[nonzero]
     fv_array[nonzero] = (
-        -pv[nonzero] * temp
+        - pv[nonzero] * temp
         - pmt[nonzero] * (1 + rate_nonzero * when[nonzero]) / rate_nonzero
         * (temp - 1)
     )

numpy_financial/tests/test_financial.py

@@ -482,10 +482,7 @@ def test_when_is_begin_decimal(self, when):
     @pytest.mark.parametrize('when', [None, 0, 'end'])
     def test_when_is_end_float(self, when):
         args = (0.075, 20, -2000, 0)
-        if when is None:
-            result = npf.fv(*args)
-        else:
-            result = npf.fv(*args, when)
+        result = npf.fv(*args) if when is None else npf.fv(*args, when)
         assert_allclose(
             result,
             86609.362673,  # Computed using Google Sheet's FV
@@ -500,10 +497,7 @@ def test_when_is_end_decimal(self, when):
             Decimal('-2000'),
             Decimal('0'),
         )
-        if when is None:
-            result = npf.fv(*args)
-        else:
-            result = npf.fv(*args, when)
+        result = npf.fv(*args) if when is None else npf.fv(*args, when)
         assert_almost_equal(result, Decimal('86609.362673'), decimal=5)
 
     def test_broadcast(self):