diff --git a/stdlib/3/subprocess.pyi b/stdlib/3/subprocess.pyi
index bd9e6cfb772e..9589371532bc 100644
--- a/stdlib/3/subprocess.pyi
+++ b/stdlib/3/subprocess.pyi
@@ -38,8 +38,8 @@ if sys.version_info >= (3, 5):
                 preexec_fn: Callable[[], Any] = ...,
                 close_fds: bool = ...,
                 shell: bool = ...,
-                cwd: _TXT = ...,
-                env: _ENV = ...,
+                cwd: Optional[_TXT] = ...,
+                env: Optional[_ENV] = ...,
                 universal_newlines: bool = ...,
                 startupinfo: Any = ...,
                 creationflags: int = ...,
@@ -63,8 +63,8 @@ if sys.version_info >= (3, 5):
                 preexec_fn: Callable[[], Any] = ...,
                 close_fds: bool = ...,
                 shell: bool = ...,
-                cwd: _TXT = ...,
-                env: _ENV = ...,
+                cwd: Optional[_TXT] = ...,
+                env: Optional[_ENV] = ...,
                 universal_newlines: bool = ...,
                 startupinfo: Any = ...,
                 creationflags: int = ...,
@@ -84,8 +84,8 @@ if sys.version_info >= (3, 3):
              preexec_fn: Callable[[], Any] = ...,
              close_fds: bool = ...,
              shell: bool = ...,
-             cwd: _TXT = ...,
-             env: _ENV = ...,
+             cwd: Optional[_TXT] = ...,
+             env: Optional[_ENV] = ...,
              universal_newlines: bool = ...,
              startupinfo: Any = ...,
              creationflags: int = ...,
@@ -103,8 +103,8 @@ else:
              preexec_fn: Callable[[], Any] = ...,
              close_fds: bool = ...,
              shell: bool = ...,
-             cwd: _TXT = ...,
-             env: _ENV = ...,
+             cwd: Optional[_TXT] = ...,
+             env: Optional[_ENV] = ...,
              universal_newlines: bool = ...,
              startupinfo: Any = ...,
              creationflags: int = ...,
@@ -124,8 +124,8 @@ if sys.version_info >= (3, 3):
                    preexec_fn: Callable[[], Any] = ...,
                    close_fds: bool = ...,
                    shell: bool = ...,
-                   cwd: _TXT = ...,
-                   env: _ENV = ...,
+                   cwd: Optional[_TXT] = ...,
+                   env: Optional[_ENV] = ...,
                    universal_newlines: bool = ...,
                    startupinfo: Any = ...,
                    creationflags: int = ...,
@@ -143,8 +143,8 @@ else:
                    preexec_fn: Callable[[], Any] = ...,
                    close_fds: bool = ...,
                    shell: bool = ...,
-                   cwd: _TXT = ...,
-                   env: _ENV = ...,
+                   cwd: Optional[_TXT] = ...,
+                   env: Optional[_ENV] = ...,
                    universal_newlines: bool = ...,
                    startupinfo: Any = ...,
                    creationflags: int = ...,
@@ -162,8 +162,8 @@ if sys.version_info >= (3, 6):
                      preexec_fn: Callable[[], Any] = ...,
                      close_fds: bool = ...,
                      shell: bool = ...,
-                     cwd: _TXT = ...,
-                     env: _ENV = ...,
+                     cwd: Optional[_TXT] = ...,
+                     env: Optional[_ENV] = ...,
                      universal_newlines: bool = ...,
                      startupinfo: Any = ...,
                      creationflags: int = ...,
@@ -186,8 +186,8 @@ elif sys.version_info >= (3, 4):
                      preexec_fn: Callable[[], Any] = ...,
                      close_fds: bool = ...,
                      shell: bool = ...,
-                     cwd: _TXT = ...,
-                     env: _ENV = ...,
+                     cwd: Optional[_TXT] = ...,
+                     env: Optional[_ENV] = ...,
                      universal_newlines: bool = ...,
                      startupinfo: Any = ...,
                      creationflags: int = ...,
@@ -207,8 +207,8 @@ elif sys.version_info >= (3, 3):
                      preexec_fn: Callable[[], Any] = ...,
                      close_fds: bool = ...,
                      shell: bool = ...,
-                     cwd: _TXT = ...,
-                     env: _ENV = ...,
+                     cwd: Optional[_TXT] = ...,
+                     env: Optional[_ENV] = ...,
                      universal_newlines: bool = ...,
                      startupinfo: Any = ...,
                      creationflags: int = ...,
@@ -227,8 +227,8 @@ else:
                      preexec_fn: Callable[[], Any] = ...,
                      close_fds: bool = ...,
                      shell: bool = ...,
-                     cwd: _TXT = ...,
-                     env: _ENV = ...,
+                     cwd: Optional[_TXT] = ...,
+                     env: Optional[_ENV] = ...,
                      universal_newlines: bool = ...,
                      startupinfo: Any = ...,
                      creationflags: int = ...,