Added file on fill() method

content/matplotlib/concepts/pyplot/terms/fill/fill.md

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+---
+Title: '.fill()'
+Description: 'Fills the area enclosed by specified x and y coordinates to create a filled polygon on the plot.'
+Subjects:
+  - 'Data Science'
+  - 'Data Visualization'
+Tags:
+  - 'Graphs'
+  - 'Libraries'
+  - 'Matplotlib'
+CatalogContent:
+  - 'learn-python-3'
+  - 'paths/computer-science'
+---
+
+The **`.fill()`** function in Matplotlib fills the area enclosed by specified x and y coordinates with color. It’s often used to highlight or emphasize regions defined by one or more polygons on a plot.
+
+## Syntax
+
+```pseudo
+matplotlib.pyplot.fill(*args, data=None, **kwargs)
+```
+
+**Parameters:**
+
+- `*args`: One or more pairs of x and y coordinates defining the polygons to fill.
+- `data`: An object (like a DataFrame or dict) that provides named variables for `x` and `y`.
+- `**kwargs`: Additional keyword arguments controlling the fill style, such as:
+  - `color` or `facecolor`: Fill color.
+  - `edgecolor`: Color of the polygon edge.
+  - `linewidth`: Width of polygon edges.
+  - `alpha`: Transparency level (0.0 to 1.0).
+  - Any other valid `Polygon` properties.
+
+**Return value:**
+
+Returns a list of `matplotlib.patches.Polygon` objects representing the filled regions.
+
+## Example 1: Filling a Rectangle Shape
+
+This example fills the area enclosed by a rectangle:
+
+```py
+import matplotlib.pyplot as plt
+
+x = [0, 3, 3, 0]
+y = [0, 0, 3, 3]
+
+plt.fill(x, y, color='green', alpha=0.75)
+plt.title('Filled Rectangle')
+plt.show()
+```
+
+The output of this code is:
+
+![Output of the first matplotlib.pyplot.fill() method example](https://raw.githubusercontent.com/Codecademy/docs/main/media/first-pyplot-fill.png)
+
+## Example 2: Filling Custom Polygon Shapes
+
+This example fills two different polygons using custom edge and fill colors:
+
+```py
+import matplotlib.pyplot as plt
+
+# Polygon 1
+a = [0, 1, 2, 1]
+b = [0, 2, 0, -2]
+plt.fill(a, b, color='skyblue', edgecolor='red', linewidth=2)
+
+# Polygon 2
+m = [0, 0, 3, 3]
+n = [0, 3, 0, 3]
+plt.fill(m, n, color='pink', alpha=0.6)
+
+plt.title('Custom Filled Polygons')
+plt.show()
+```
+
+The output of this code is:
+
+![Output of the second matplotlib.pyplot.fill() method example](https://raw.githubusercontent.com/Codecademy/docs/main/media/second-pyplot-fill.png)