How to choose a font with Text object?

This code does not change the font and letter become distorted (click on the image to enlarge and look at letters: `B, D, f, g, P, U...`):
```
script = '''
AaBbCcDdEeFfGg
HhIiJjKkLlMmNn
OoPpQqRrSsTtUu
VvWwXxYyZz
'''

class WriteText(Scene):
def construct(self):
text = Text(script, font='/usr/share/fonts/truetype/open-sans/OpenSans-Regular.ttf')
self.play(Write(text))
self.wait(.1)
```
`!python3 -m manim example_scenes.py WriteText -r 480,854`

If I change this line the result is kind of similar to the target, but I can't choose `regular` and letters are distorted (look at the small `g` it has a stair on the top):
`text = Text(script, font="Open Sans")`