Merge e509082 into 73124de

src/dotenv/__init__.py

@@ -1,6 +1,9 @@
-from typing import Any, Optional
+from .compat import IS_TYPE_CHECKING
 from .main import load_dotenv, get_key, set_key, unset_key, find_dotenv, dotenv_values
 
+if IS_TYPE_CHECKING:
+    from typing import Any, Optional
+
 
 def load_ipython_extension(ipython):
     # type: (Any) -> None

src/dotenv/cli.py

@@ -1,6 +1,5 @@
 import os
 import sys
-from typing import Any, List
 
 try:
     import click
@@ -9,9 +8,13 @@
                      'Run pip install "python-dotenv[cli]" to fix this.')
     sys.exit(1)
 
+from .compat import IS_TYPE_CHECKING
 from .main import dotenv_values, get_key, set_key, unset_key, run_command
 from .version import __version__
 
+if IS_TYPE_CHECKING:
+    from typing import Any, List
+
 
 @click.group()
 @click.option('-f', '--file', default=os.path.join(os.getcwd(), '.env'),

src/dotenv/compat.py

@@ -1,3 +1,4 @@
+import os
 import sys
 
 if sys.version_info >= (3, 0):
@@ -6,3 +7,15 @@
     from StringIO import StringIO  # noqa
 
 PY2 = sys.version_info[0] == 2  # type: bool
+
+
+def is_type_checking():
+    # type: () -> bool
+    try:
+        from typing import TYPE_CHECKING
+    except ImportError:
+        return False
+    return TYPE_CHECKING
+
+
+IS_TYPE_CHECKING = os.environ.get("MYPY_RUNNING", is_type_checking())

src/dotenv/main.py

@@ -9,15 +9,17 @@
 import sys
 from subprocess import Popen
 import tempfile
-from typing import (Any, Dict, Iterator, List, Match, NamedTuple, Optional,  # noqa
-                    Pattern, Union, TYPE_CHECKING, Text, IO, Tuple)  # noqa
 import warnings
 from collections import OrderedDict
 from contextlib import contextmanager
 
-from .compat import StringIO, PY2
+from .compat import StringIO, PY2, IS_TYPE_CHECKING
 
-if TYPE_CHECKING:  # pragma: no cover
+if IS_TYPE_CHECKING:  # pragma: no cover
+    from typing import (
+        Dict, Iterator, List, Match, Optional, Pattern, Union,
+        Text, IO, Tuple
+    )
     if sys.version_info >= (3, 6):
         _PathLike = os.PathLike
     else:
@@ -59,10 +61,14 @@
 
 _escape_sequence = re.compile(r"\\[\\'\"abfnrtv]")  # type: Pattern[Text]
 
-
-Binding = NamedTuple("Binding", [("key", Optional[Text]),
-                                 ("value", Optional[Text]),
-                                 ("original", Text)])
+try:
+    from typing import NamedTuple, Optional, Text
+    Binding = NamedTuple("Binding", [("key", Optional[Text]),
+                                     ("value", Optional[Text]),
+                                     ("original", Text)])
+except ImportError:
+    from collections import namedtuple
+    Binding = namedtuple("Binding", ["key", "value", "original"])
 
 
 def decode_escapes(string):