<s> from sympy import ( Symbol , gamma , expand_func , beta , digamma , diff ) <EOL> def test_beta ( ) : <EOL> x , y = Symbol ( '<STR_LIT:x>' ) , Symbol ( '<STR_LIT:y>' ) <EOL> assert isinstance ( beta ( x , y ) , beta ) <EOL> assert expand_func ( beta ( x , y ) ) == gamma ( x ) * gamma ( y ) / gamma ( x + y ) <EOL> assert expand_func ( beta ( x , y ) - beta ( y , x ) ) == <NUM_LIT:0> <EOL> assert expand_func ( beta ( x , y ) ) == expand_func ( beta ( x , y + <NUM_LIT:1> ) + beta ( x + <NUM_LIT:1> , y ) ) . simplify ( ) <EOL> assert diff ( beta ( x , y ) , x ) == beta ( x , y ) * ( digamma ( x ) - digamma ( x + y ) ) <EOL> assert diff ( beta ( x , y ) , y ) == beta ( x , y ) * ( digamma ( y ) - digamma ( x + y ) ) </s>
