added documentation for standard deviation function

Author: nicolelink33

src/dumbpy/std_deviation.py

@@ -0,0 +1,28 @@
+"""
+A module that calculates the standard deviation of a list of numbers.
+
+"""
+
+def std_deviation(input):
+    """
+    Calculate the standard deviation of the inputted list and return the result.
+
+    Parameters
+    ----------
+    input : list
+        A list of numbers.
+
+    Returns
+    -------
+    float
+        The standard deviation of the list of numbers.
+
+    Examples
+    --------
+    >>> std_deviation([1, 1, 1, 1])
+    0
+    >>> add_numbers([1, 0, 1, 0])
+    0.5
+
+    """
+