def prep_gate(self, circuit, qreg, op):
if self.prep_fun is None:<EOL><INDENT>pass<EOL><DEDENT>else:<EOL><INDENT>self.prep_fun(circuit, qreg, op)<EOL><DEDENT>
Add state preparation gates to a circuit.

Args:
    circuit (QuantumCircuit): circuit to add a preparation to.
    qreg (tuple(QuantumRegister,int)): quantum register to apply
    preparation to.
    op (tuple(str, int)): the basis label and index for the
    preparation op.