The Python `ValueError`

is an exception that occurs when a function receives an argument of the correct data type but an inappropriate value. This error usually occurs in mathematical operations that require a certain kind of value.

## What Causes ValueError

The Python `ValueError`

is raised when the wrong value is assigned to an object. This can happen if the value is invalid for a given operation, or if the value does not exist. For example, if a negative integer is passed to a square root operation, a `ValueError`

is raised.

## Python ValueError Example

Here’s an example of a Python `ValueError`

raised when trying to perform a square root operation on a negative number:

```
import math
math.sqrt(-100)
```

In the above example, a negative integer is passed to the `math.sqrt()`

function. Since the function expects a positive integer, running the above code raises a `ValueError`

:

```
Traceback (most recent call last):
File "test.py", line 3, in <module>
math.sqrt(-100)
ValueError: math domain error
```

## How to Fix ValueError Exceptions in Python

To resolve the `ValueError`

in Python code, a try-except block can be used. The lines of code that can throw the `ValueError`

should be placed in the `try`

block, and the `except`

block can catch and handle the error.

Using the above approach, the previous example can be updated to handle the error:

```
import math
try:
math.sqrt(-100)
except ValueError:
print('Positive number expected for square root operation')
```

Here, a check is performed for the `ValueError`

using the try-except block. When the above code is executed, the `except`

block catches the `ValueError`

and handles it, producing the following output:

```
Positive number expected for square root operation
```

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