# con_cat





Given two strings, append them together (known as "concatenation") and return the result. However, if the concatenation creates a double-char, then omit one of the chars, so "abc" and "cat" yields "abcat".

This exercise was taken from [codingbat.com](https://codingbat.com/prob/p132118) and has been adapted for the Python language. There are many great programming exercises there, but the majority are created for Java.






### Test 1
**Input:**
```
'abc'
'cat'
```
**Output:**
```
'abcat'
```
### Test 2
**Input:**
```
'dog'
'cat'
```
**Output:**
```
'dogcat'
```
### Test 3
**Input:**
```
'abc'
''
```
**Output:**
```
'abc'
```
### Test 4
**Input:**
```
''
'cat'
```
**Output:**
```
'cat'
```
### Test 5
**Input:**
```
'pig'
'g'
```
**Output:**
```
'pig'
```
### Test 6
**Input:**
```
'pig'
'doggy'
```
**Output:**
```
'pigdoggy'
```