------
## 最终结论
```python
from typing import List

def concatenate(strings: List[str]) -> str:
    """ Concatenate list of strings into a single string
    >>> concatenate([])
    ''
    >>> concatenate(['a', 'b', 'c'])
    'abc'
    """
    result = ''
    for string in strings:
        result += string
    return result
```