Add documentation for Python binascii.a2b_hex() method

content/python/concepts/binascii-module/terms/a2b-hex/a2b-hex.md

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+---
+Title: '.a2b_hex()'
+Description: 'Decodes a hexadecimal (base-16) encoded ASCII string into the original binary data (bytes).'
+Subjects:
+  - 'Computer Science'
+  - 'Data Science'
+Tags:
+  - 'Encoding'
+  - 'Functions'
+CatalogContent:
+  - 'learn-python-3'
+  - 'paths/computer-science'
+---
+
+The **`binascii.a2b_hex()`** function in Python decodes a hexadecimal (base-16) encoded ASCII string into its original binary form. It translates pairs of hexadecimal digits into corresponding byte values, effectively reversing the process of hex encoding.
+
+## Syntax
+
+```pseudo
+binascii.a2b_hex(string)
+```
+
+**Parameters:**
+
+- `string`: A bytes or bytearray object containing hexadecimal (base-16) encoded data. Each pair of hex digits represents one byte, so the length must be even.
+
+**Return value:**
+
+Returns a bytes object containing the binary data decoded from the given hexadecimal input.
+
+**Exceptions:**
+
+Raises `binascii.Error` if the input contains an odd number of hexadecimal digits or contains invalid characters.
+
+## Example
+
+In this example, the hexadecimal string `"48656C6C6F"` is decoded into its corresponding binary data and then interpreted as ASCII text:
+
+```py
+import binascii
+
+# Convert hexadecimal string to binary
+hex_string = "48656C6C6F"
+binary_data = binascii.a2b_hex(hex_string)
+
+print("Hexadecimal:", hex_string)
+print("Binary data:", binary_data)
+print("Decoded text:", binary_data.decode('utf-8'))
+```
+
+The output of this code is:
+
+```shell
+Hexadecimal: 48656C6C6F
+Binary data: b'Hello'
+Decoded text: Hello
+```
+
+## Codebyte Example
+
+Run the following code to see `.a2b_hex()` in action with different scenarios:
+
+```codebyte/python
+import binascii
+
+# Example 1: Convert hexadecimal to binary
+hex_data = "50797468"
+result = binascii.a2b_hex(hex_data)
+print("Hex:", hex_data)
+print("Binary:", result)
+print("As text:", result.decode('utf-8'))
+
+# Example 2: Uppercase and lowercase work the same
+hex_upper = "414243"
+hex_lower = "414243"
+print("\nUppercase result:", binascii.a2b_hex(hex_upper))
+print("Lowercase result:", binascii.a2b_hex(hex_lower))
+
+# Example 3: Converting numeric data
+hex_numbers = "010203040A0B0C"
+binary_numbers = binascii.a2b_hex(hex_numbers)
+print("\nHex numbers:", hex_numbers)
+print("Binary:", binary_numbers)
+print("Byte values:", list(binary_numbers))
+```