Add type hints to the unique_name function and the GMTTempFile class (#3440)

Author: seisman

pygmt/helpers/tempfile.py

@@ -12,17 +12,17 @@
 from packaging.version import Version
 
 
-def unique_name():
+def unique_name() -> str:
     """
     Generate a unique name.
 
-    Useful for generating unique names for figures (otherwise GMT will plot
-    everything on the same figure instead of creating a new one).
+    Useful for generating unique names for figures. Otherwise GMT will plot everything
+    on the same figure instead of creating a new one.
 
     Returns
     -------
-    name : str
-        A unique name generated by :func:`uuid.uuid4`
+    name
+        A unique name generated by :func:`uuid.uuid4`.
     """
     return uuid.uuid4().hex
 
@@ -31,15 +31,14 @@ class GMTTempFile:
     """
     Context manager for creating closed temporary files.
 
-    This class does not return a file-like object. So, you can't do
-    ``for line in GMTTempFile()``, for example, or pass it to things that
-    need file objects.
+    This class does not return a file-like object. So, you can't iterate over the object
+    like ``for line in GMTTempFile()``, or pass it to things that need a file object.
 
     Parameters
     ----------
-    prefix : str
+    prefix
         The temporary file name begins with the prefix.
-    suffix : str
+    suffix
         The temporary file name ends with the suffix.
 
     Examples
@@ -60,7 +59,10 @@ class GMTTempFile:
     [0. 0. 0.] [1. 1. 1.] [2. 2. 2.]
     """
 
-    def __init__(self, prefix="pygmt-", suffix=".txt"):
+    def __init__(self, prefix: str = "pygmt-", suffix: str = ".txt"):
+        """
+        Initialize the object.
+        """
         with NamedTemporaryFile(prefix=prefix, suffix=suffix, delete=False) as tmpfile:
             self.name = tmpfile.name
 
@@ -76,33 +78,33 @@ def __exit__(self, *args):
         """
         Path(self.name).unlink(missing_ok=True)
 
-    def read(self, keep_tabs=False):
+    def read(self, keep_tabs: bool = False) -> str:
         """
         Read the entire contents of the file as a Unicode string.
 
         Parameters
         ----------
-        keep_tabs : bool
+        keep_tabs
             If False, replace the tabs that GMT uses with spaces.
 
         Returns
         -------
-        content : str
+        content
             Content of the temporary file as a Unicode string.
         """
         content = Path(self.name).read_text(encoding="utf8")
         if not keep_tabs:
             content = content.replace("\t", " ")
         return content
 
-    def loadtxt(self, **kwargs):
+    def loadtxt(self, **kwargs) -> np.ndarray:
         """
         Load data from the temporary file using numpy.loadtxt.
 
         Parameters
         ----------
-        kwargs : dict
-            Any keyword arguments that can be passed to numpy.loadtxt.
+        kwargs
+            Any keyword arguments that can be passed to :func:`np.loadtxt`.
 
         Returns
         -------