title: How to make user input not case sensitive?
body: <p>I want to create a function to filter which files I want to open and which months and day specifically. That way, the users need to input which city (files) they want to analyze on which particular month or day. However, I want the user to be able to input something that is not case sensitive.</p>
  <p>For example, the user can input 'chicago'/'CHICAGO&quot;/&quot;ChIcAgO&quot; and the it still give you the right output and not the error handling message. Here is the code I use:</p>
  <pre><code>def get_filters ():
  
      city_options = ['Chicago','New York City','Washington']
      month_options = ['January','February','March','April','May','June','All']
      day_options = ['Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sunday','All']
      while True:
          try:
              city = city_options.index(input('\nInsert name of the city to analyze! (Chicago, New York City, Washington)\n'))
              month = month_options.index(input('\nInsert month to filter by or &quot;All&quot; to apply no month filter! (January, February, etc.)\n'))
              day = day_options.index(input('\nInsert day of the week to filter by or &quot;All&quot; to apply no day filter! (Monday, Tuesday, etc.)\n'))
              return city_options[city].lower(), month_options[month].lower(), day_options[day].lower()
          except ValueError:
              print (&quot;Your previous choice is not available. Please try again&quot;)
  
  def load_data (city,month,day):
     
      #load data file into DataFrame
      df = pd.read_csv(CITY_DATA[city].lower())
  
      #convert start time column (string) to datetime
      df['Start Time']=pd.to_datetime(df['Start Time'])
  
      #create new column to extract month and day of the week from start time
      df['Month'] = df['Start Time'].dt.month
      df['Day_of_Week'] = df['Start Time'].dt.weekday_name
  
      #filter by month if applicable
      if month.lower()!= 'All':
          #use the index of the month list to get corresponding into
          months = ['January', 'February', 'March', 'April', 'May', 'June']
          month = months.index(month) + 1
          #filter by month to create new dataframes
          df = df[df['Month'] == month]
  
      if day.lower()!= 'All':
          #filter by day_of_week to create new DataFrames
          df =df[df['Day_of_Week'] == day]
  
      return(df)
  </code></pre>