def create_package(self, assay=None, mass=<NUM_LIT:0.0>, normalise=True):
if assay is None:<EOL><INDENT>return MaterialPackage(self, self.create_empty_assay())<EOL><DEDENT>if normalise:<EOL><INDENT>assay_total = self.get_assay_total(assay)<EOL><DEDENT>else:<EOL><INDENT>assay_total = <NUM_LIT:1.0><EOL><DEDENT>masses = [(mass * m) / assay_total for m in self.assays[assay]]<EOL>return MaterialPackage(self, masses)<EOL>
Create a MaterialPackage based on the specified parameters.

:param assay: The name of the assay based on which the package must be
  created.
:param mass: [kg] The mass of the package.
:param normalise: Indicates whether the assay must be normalised before
  creating the package.

:returns: The created MaterialPackage.