Remove unnecessary import (#296)

* Remove unnecessary import

* fix

torchani/aev.py

@@ -2,20 +2,19 @@
 import torch
 from . import _six  # noqa:F401
 import math
-from torch import Tensor
 from typing import Tuple
 
 
 # @torch.jit.script
 def cutoff_cosine(distances, cutoff):
-    # type: (Tensor, float) -> Tensor
+    # type: (torch.Tensor, float) -> torch.Tensor
     # assuming all elements in distances are smaller than cutoff
     return 0.5 * torch.cos(distances * (math.pi / cutoff)) + 0.5
 
 
 # @torch.jit.script
 def radial_terms(Rcr, EtaR, ShfR, distances):
-    # type: (float, Tensor, Tensor, Tensor) -> Tensor
+    # type: (float, torch.Tensor, torch.Tensor, torch.Tensor) -> torch.Tensor
     """Compute the radial subAEV terms of the center atom given neighbors
 
     This correspond to equation (3) in the `ANI paper`_. This function just
@@ -43,7 +42,7 @@ def radial_terms(Rcr, EtaR, ShfR, distances):
 
 # @torch.jit.script
 def angular_terms(Rca, ShfZ, EtaA, Zeta, ShfA, vectors1, vectors2):
-    # type: (float, Tensor, Tensor, Tensor, Tensor, Tensor, Tensor) -> Tensor
+    # type: (float, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor) -> torch.Tensor
     """Compute the angular subAEV terms of the center atom given neighbor pairs.
 
     This correspond to equation (4) in the `ANI paper`_. This function just
@@ -96,7 +95,7 @@ def compute_shifts(cell, pbc, cutoff):
         :class:`torch.Tensor`: long tensor of shifts. the center cell and
             symmetric cells are not included.
     """
-    # type: (Tensor, Tensor, float) -> Tensor
+    # type: (torch.Tensor, torch.Tensor, float) -> torch.Tensor
     reciprocal_cell = cell.inverse().t()
     inv_distances = reciprocal_cell.norm(2, -1)
     num_repeats = torch.ceil(cutoff * inv_distances).to(torch.long)
@@ -136,7 +135,7 @@ def neighbor_pairs(padding_mask, coordinates, cell, shifts, cutoff):
         cutoff (float): the cutoff inside which atoms are considered pairs
         shifts (:class:`torch.Tensor`): tensor of shape (?, 3) storing shifts
     """
-    # type: (Tensor, Tensor, Tensor, Tensor, float) -> Tuple[Tensor, Tensor, Tensor, Tensor]
+    # type: (torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, float) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]
 
     coordinates = coordinates.detach()
     cell = cell.detach()