qat.core.circuit_builder

`qat.core.circuit_builder.builder.VariableNameNotAvailable`	Exception raised when a variable is redefined using the same name.
`qat.core.circuit_builder.matrix_util.default_gate_set()`	Generates a fresh default gate set
`qat.core.circuit_builder.matrix_util.get_param_generator()`	Returns a map containing the 4 default parametrized gates generators
`qat.core.circuit_builder.matrix_util.get_predef_generator()`	Returns a map of all the matrices of constant gates in the default gate set