old_contents: class AstroLabels(object):
      """Formatted strings for labeling astronomy plots."""
      def __init__(self):
          # units
          self.mpc = " $[\mathrm{Mpc}]$"
          self.msun_pc2 = " $[M_{\odot}\ \mathrm{pc}^{-2}]$"
      
          # quantities
          self.sgma = "$\Sigma(R)$"
          self.sgma_off = "$\Sigma^\mathrm{off}(R)$"
          self.delta = "$\Delta$"
  
          # dimensionful quantities
          self.r_mpc = "$R$" + self.mpc
          self.sigma = self.sgma + self.msun_pc2
          self.sigma_off = self.sgma_off + self.msun_pc2
          self.dsigma = self.delta + self.sigma
          self.dsigma_off = self.delta + self.sigma_off
  
new_contents: class AstroLabels(object):
      """Formatted strings for labeling astronomy plots."""
      def __init__(self):
          # units
          self.mpc = " $[\mathrm{Mpc}]$"
          self.msun_pc2 = " $[M_{\odot}\ \mathrm{pc}^{-2}]$"
  
          # quantities
          self.sgma = "$\Sigma(R)$"
          self.sgma_off = "$\Sigma^\mathrm{off}(R)$"
          self.delta = "$\Delta$"
  
          # dimensionful quantities
          self.r_mpc = "$R$" + self.mpc
          self.sigma = self.sgma + self.msun_pc2
          self.sigma_off = self.sgma_off + self.msun_pc2
          self.dsigma = self.delta + self.sigma
          self.dsigma_off = self.delta + self.sigma_off
  
subject: Remove whitespace