write a regex to extract dates in different ways python regex : i would like to extract the date of birth from these text. there are four conditions: 

    keywords to match 
    
        Date of Birth 
        date of birth:
        D.O.B:
        DOB:

The strings like that: 

    text = "my name is adam my DOB: 30-11-1988 and i play football since 20-2011"
    text = "my name is D.O.B: 20/MAY/1987 and i play football since 20-2011"
    text = "my Date of Birth 12-7-1970 and i start study since 20-2011"
    text = "my date of birth: 20/9/1970 "


