Revision2

tidy3d/plugins/dispersion/fit.py

@@ -1,5 +1,6 @@
 """Fit PoleResidue Dispersion models to optical NK data
 """
+from __future__ import annotations
 
 from typing import Tuple, List, Optional
 import csv
@@ -564,7 +565,9 @@ def _validate_url_load(data_load: List):
             raise ValidationError("Invalid URL. Too many k labels.")
 
     @classmethod
-    def from_url(cls, url_file: str, delimiter: str = ",", ignore_k: bool = False, **kwargs):
+    def from_url(
+        cls, url_file: str, delimiter: str = ",", ignore_k: bool = False, **kwargs
+    ) -> DispersionFitter:
         """loads :class:`DispersionFitter` from url linked to a csv/txt file that
         contains wavelength (micron), n, and optionally k data. Preferred from
         refractiveindex.info.
@@ -652,7 +655,7 @@ def from_url(cls, url_file: str, delimiter: str = ",", ignore_k: bool = False, *
         return cls(wvl_um=n_lam[:, 0], n_data=n_lam[:, 1], **kwargs)
 
     @classmethod
-    def from_file(cls, fname: str, **loadtxt_kwargs):
+    def from_file(cls, fname: str, **loadtxt_kwargs) -> DispersionFitter:
         """Loads :class:`DispersionFitter` from file containing wavelength, n, k data.
 
         Parameters
@@ -705,7 +708,7 @@ def from_complex_permittivity(
         eps_real: ArrayFloat1D,
         eps_imag: ArrayFloat1D = None,
         wvl_range: Tuple[Optional[float], Optional[float]] = (None, None),
-    ):
+    ) -> DispersionFitter:
         """Loads :class:`DispersionFitter` from wavelength and complex relative permittivity data
 
         Parameters
@@ -737,7 +740,7 @@ def from_loss_tangent(
         eps_real: ArrayFloat1D,
         loss_tangent: ArrayFloat1D,
         wvl_range: Tuple[Optional[float], Optional[float]] = (None, None),
-    ):
+    ) -> DispersionFitter:
         """Loads :class:`DispersionFitter` from wavelength and loss tangent data.
 
         Parameters