Use names SEEK_SET, etc instead of magic number (GH-12057)

The previous code hardcoded `SEEK_SET`, etc. While it's very unlikely
that these values will change, it's best to use the definitions to avoid
there being mismatches in behavior with the code in the future.

Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index e4a879941e1..b0593c3d3ab 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -2386,18 +2386,18 @@ class TextIOWrapper(TextIOBase):
             raise ValueError("tell on closed file")
         if not self._seekable:
             raise UnsupportedOperation("underlying stream is not seekable")
-        if whence == 1: # seek relative to current position
+        if whence == SEEK_CUR:
             if cookie != 0:
                 raise UnsupportedOperation("can't do nonzero cur-relative seeks")
             # Seeking to the current position should attempt to
             # sync the underlying buffer with the current position.
             whence = 0
             cookie = self.tell()
-        if whence == 2: # seek relative to end of file
+        elif whence == SEEK_END:
             if cookie != 0:
                 raise UnsupportedOperation("can't do nonzero end-relative seeks")
             self.flush()
-            position = self.buffer.seek(0, 2)
+            position = self.buffer.seek(0, whence)
             self._set_decoded_chars('')
             self._snapshot = None
             if self._decoder: