'Returns the square root of a non-negative number to context precision.
If the result must be inexact, it is rounded using the round-half-even
algorithm.
>>> ExtendedContext.sqrt(Decimal(\'0\'))
Decimal("0")
>>> ExtendedContext.sqrt(Decimal(\'-0\'))
Decimal("-0")
>>> ExtendedContext.sqrt(Decimal(\'0.39\'))
Decimal("0.624499800")
>>> ExtendedContext.sqrt(Decimal(\'100\'))
Decimal("10")
>>> ExtendedContext.sqrt(Decimal(\'1\'))
Decimal("1")
>>> ExtendedContext.sqrt(Decimal(\'1.0\'))
Decimal("1.0")
>>> ExtendedContext.sqrt(Decimal(\'1.00\'))
Decimal("1.0")
>>> ExtendedContext.sqrt(Decimal(\'7\'))
Decimal("2.64575131")
>>> ExtendedContext.sqrt(Decimal(\'10\'))
Decimal("3.16227766")
>>> ExtendedContext.prec
9'

def sqrt(self, a):

    return a.sqrt(context=self)
