fix timestamp Docstring validation err

Author: uditbaliyan

pandas/_libs/tslibs/nattype.pyx

@@ -1013,6 +1013,23 @@ class NaTType(_NaT):
         """
         Return POSIX timestamp as float.
 
+        This method converts the `Timestamp` object to a POSIX timestamp, which is
+        the number of seconds since the Unix epoch (January 1, 1970). The returned
+        value is a floating-point number, where the integer part represents the
+        seconds, and the fractional part represents the microseconds.
+
+        Returns
+        -------
+        float
+            The POSIX timestamp representation of the `Timestamp` object.
+
+        See Also
+        --------
+        Timestamp.fromtimestamp : Construct a `Timestamp` from a POSIX timestamp.
+        datetime.datetime.timestamp : Equivalent method from the `datetime` module.
+        Timestamp.to_pydatetime : Convert the `Timestamp` to a `datetime` object.
+        Timestamp.to_datetime64 : Converts `Timestamp` to `numpy.datetime64`.
+
         Examples
         --------
         >>> ts = pd.Timestamp('2020-03-14T15:32:52.192548')