old_contents: """
  The unyt package.
  
  Note that the symbols defined in :mod:`unyt.physical_constants` and
  :mod:`unyt.unit_symbols` are importable from this module. For example::
  
      >>> from unyt import km, clight
      >>> print((km/clight).to('ns'))
      3335.64095198152 ns
  
  In addition, the following functions and classes are importable from the
  top-level ``unyt`` namespace:
  
  * :func:`unyt.array.loadtxt`
  * :func:`unyt.array.savetxt`
  * :func:`unyt.array.uconcatenate`
  * :func:`unyt.array.ucross`
  * :func:`unyt.array.udot`
  * :func:`unyt.array.uhstack`
  * :func:`unyt.array.uintersect1d`
  * :func:`unyt.array.unorm`
  * :func:`unyt.array.ustack`
  * :func:`unyt.array.uunion1d`
  * :func:`unyt.array.uvstack`
  * :class:`unyt.array.unyt_array`
  * :class:`unyt.array.unyt_quantity`
  * :func:`unyt.unit_object.define_unit`
  * :class:`unyt.unit_object.Unit`
  * :class:`unyt.unit_registry.UnitRegistry`
  """
  
  # -----------------------------------------------------------------------------
  # Copyright (c) 2018, yt Development Team.
  #
  # Distributed under the terms of the Modified BSD License.
  #
  # The full license is in the LICENSE file, distributed with this software.
  # -----------------------------------------------------------------------------
  
  from ._version import get_versions
  
  from unyt import unit_symbols
  from unyt import physical_constants
  
  from unyt.array import (  # NOQA
      loadtxt,
      savetxt,
      uconcatenate,
      ucross,
      udot,
      uhstack,
      uintersect1d,
      unorm,
      ustack,
      uunion1d,
      uvstack,
      unyt_array,
      unyt_quantity
  )
  from unyt.unit_object import (  # NOQA
      Unit,
      define_unit
  )
  from unyt.unit_registry import UnitRegistry  # NOQA
  
  # function to only import quantities into this namespace
  # we go through the trouble of doing this instead of "import *"
  # to avoid including extraneous variables (e.g. floating point
  # constants used to *construct* a physical constant) in this namespace
  def import_quantities(module, global_namespace):
      for key, value in module.__dict__.items():
          if isinstance(value, unyt_quantity):
              global_namespace[key] = value
  
  
  import_quantities(unit_symbols, globals())
  import_quantities(physical_constants, globals())
  
  del import_quantities
  
  __version__ = get_versions()['version']
  del get_versions
  
new_contents: """
  The unyt package.
  
  Note that the symbols defined in :mod:`unyt.physical_constants` and
  :mod:`unyt.unit_symbols` are importable from this module. For example::
  
      >>> from unyt import km, clight
      >>> print((km/clight).to('ns'))
      3335.64095198152 ns
  
  In addition, the following functions and classes are importable from the
  top-level ``unyt`` namespace:
  
  * :func:`unyt.array.loadtxt`
  * :func:`unyt.array.savetxt`
  * :func:`unyt.array.uconcatenate`
  * :func:`unyt.array.ucross`
  * :func:`unyt.array.udot`
  * :func:`unyt.array.uhstack`
  * :func:`unyt.array.uintersect1d`
  * :func:`unyt.array.unorm`
  * :func:`unyt.array.ustack`
  * :func:`unyt.array.uunion1d`
  * :func:`unyt.array.uvstack`
  * :class:`unyt.array.unyt_array`
  * :class:`unyt.array.unyt_quantity`
  * :func:`unyt.unit_object.define_unit`
  * :class:`unyt.unit_object.Unit`
  * :class:`unyt.unit_registry.UnitRegistry`
  """
  
  # -----------------------------------------------------------------------------
  # Copyright (c) 2018, yt Development Team.
  #
  # Distributed under the terms of the Modified BSD License.
  #
  # The full license is in the LICENSE file, distributed with this software.
  # -----------------------------------------------------------------------------
  
  from ._version import get_versions
  
  from unyt import unit_symbols
  from unyt import physical_constants
  
  from unyt.array import (  # NOQA
      loadtxt,
      savetxt,
      uconcatenate,
      ucross,
      udot,
      uhstack,
      uintersect1d,
      unorm,
      ustack,
      uunion1d,
      uvstack,
      unyt_array,
      unyt_quantity
  )
  from unyt.unit_object import (  # NOQA
      Unit,
      define_unit
  )
  from unyt.unit_registry import UnitRegistry  # NOQA
  
  
  # function to only import quantities into this namespace
  # we go through the trouble of doing this instead of "import *"
  # to avoid including extraneous variables (e.g. floating point
  # constants used to *construct* a physical constant) in this namespace
  def import_quantities(module, global_namespace):
      for key, value in module.__dict__.items():
          if isinstance(value, unyt_quantity):
              global_namespace[key] = value
  
  
  import_quantities(unit_symbols, globals())
  import_quantities(physical_constants, globals())
  
  del import_quantities
  
  __version__ = get_versions()['version']
  del get_versions
  
subject: fix pep8