title: Numpy log10 function: AttributeError: 'float' object has no attribute 'log10'
body: <pre><code>import numpy as np
  import astropy as ap
  
  def mass(FWHM, lumi):
      abs_lumi = bhm.L_1450(lumi)
      s1 = (FWHM/1000)
      s2 = ((abs_lumi)/(10**44))
      s = [(s1**2)*(s2**0.53)]
      #mass = np.log10((s1**2)*(s2**0.53)) + 6.66 #old way, didn't work
      mass = np.log10(s) + 6.66
      return mass
  </code></pre>
  
  <p>I'm trying to use the numpy log10 function, but I keep getting an error that reads:</p>
  
  <pre><code>AttributeError: 'float' object has no attribute 'log10'
  </code></pre>
  
  <p>I tried putting my argument into a list (s variable), but I got the same error message. FWHM and lumi are both numbers with decimal points (I think they're called floating point numbers).</p>