This is my complete text: 

```
RETENTION
Liability in excess of the Retention
The Retention shall be borne by the Named Insured and the Insurer shall only be liable for Loss once the Retention has been fully eroded. The Retention shall apply until such time as it has been fully eroded after which no Retention shall apply.
Erosion of the Retention
The Retention shall be eroded by Loss for which the Insurer would be liable under this Policy but for the Retention.

```

I want to extract the whole RETENTION paragraph.

This was my code to extract the sentences which have a specific word (here: Retention).

```
abc3=([sentence + '.' for sentence in txt_trim_string.split('.') if 'RETENTION' in sentence])

```

But this gave the output as:

```
RETENTION
Liability in excess of the Retention
The Retention shall be borne by the Named Insured and the Insurer shall only be liable for Loss once the Retention has been fully eroded.

```

I also want to include:

```
Erosion of the Retention
The Retention shall be eroded by Loss for which the Insurer would be liable under this Policy but for the Retention.

```

How can I do that?